The Case for Novak Djokovic … and Roger Federer … and Rafael Nadal

By winning the US Open last weekend and increasing his career total to ten Grand Slams, Novak Djokovic has pushed himself even further into conversations about the greatest of all time. At the very least, his 2015 season is shaping up to be one of the best in tennis history.

A recent FiveThirtyEight article introduced Elo ratings into the debate, showing that Djokovic’s career peak–achieved earlier this year at the French Open–is the highest of anyone’s, just above 2007 Roger Federer and 1980 Bjorn Borg. In implementing my own Elo ratings, I’ve discovered just how close those peaks are.

Here are my results for the top 15 peaks of all time [1]:

Player                 Year   Elo  
Novak Djokovic         2015  2525  
Roger Federer          2007  2524  
Bjorn Borg             1980  2519  
John McEnroe           1985  2496  
Rafael Nadal           2013  2489  
Ivan Lendl             1986  2458  
Andy Murray            2009  2388  
Jimmy Connors          1979  2384  
Boris Becker           1990  2383  
Pete Sampras           1994  2376  
Andre Agassi           1995  2355  
Mats Wilander          1984  2355  
Juan Martin del Potro  2009  2352  
Stefan Edberg          1988  2346  
Guillermo Vilas        1978  2325

A one-point gap is effectively nothing: It means that peak Djokovic would have a 50.1% chance of beating peak Federer. The 35-point gap separating Novak from peak Rafael Nadal is considerably more meaningful, implying that the better player has a 55% chance of winning.

Surface-specific Elo

If we limit our scope to hard-court matches, Djokovic is still a very strong contender, but Fed’s 2007 peak is clearly the best of all time:

Player          Year  Hard Ct Elo  
Roger Federer   2007         2453  
Novak Djokovic  2014         2418  
Ivan Lendl      1989         2370  
Pete Sampras    1997         2356  
Rafael Nadal    2014         2342  
John McEnroe    1986         2332  
Andy Murray     2009         2330  
Andre Agassi    1995         2326  
Stefan Edberg   1987         2285  
Lleyton Hewitt  2002         2262

Ivan Lendl and Pete Sampras make much better showings on this list than on the overall ranking. Still, they are far behind Fed and Novak–the roughly 100-point difference between peak Fed and peak Pete is equivalent to a 64% probability that the higher-rated player would win.

On clay, I’ll give you three guesses who tops the list–and your first two guesses don’t count. It isn’t even close:

Player           Year  Clay Ct Elo  
Rafael Nadal     2009         2550  
Bjorn Borg       1982         2475  
Novak Djokovic   2015         2421  
Ivan Lendl       1988         2408  
Mats Wilander    1984         2386  
Roger Federer    2009         2343  
Jose Luis Clerc  1981         2318  
Guillermo Vilas  1982         2316  
Thomas Muster    1996         2313  
Jimmy Connors    1980         2307

Borg was great, but Nadal is in another league entirely. Though Djokovic has pushed Nadal out of many greatest-of-all-time debates–at least for the time being–there’s little doubt that Rafa is the greatest clay court player of all time, and likely the most dominant player in tennis history on any single surface.

Djokovic is well back of both Nadal and Borg, but in his favor, he’s the only player ranked in the top three for both major surfaces.

The survivor

As the second graph in the 538 article shows, Federer stands out as the greatest player of all time at his age. Most players have retired long before their 34th birthday, and even those who stick around aren’t usually contesting Grand Slam finals. In fact, Federer’s Elo rating of 2393 after his US Open semifinal win against Stanislas Wawrinka last week would rank as the sixth-highest peak of all time, behind Lendl and just ahead of Andy Murray.

Here are the top ten Elo peaks for players over 34:

Player         Age   34+ Elo  
Roger Federer  34.1     2393  
Jimmy Connors  34.1     2234  
Andre Agassi   35.3     2207  
Rod Laver      36.6     2207  
Ken Rosewall   37.4     2195  
Tommy Haas     35.3     2111  
Arthur Ashe    35.7     2107  
Ivan Lendl     34.1     2054  
Andres Gimeno  35.0     2035  
Mark Cox       34.0     2014

The 160-point gap between Federer and Jimmy Connors implies that 34-year-old Fed would win about 70% of the time against 34-year-old Connors. No one has ever sustained this level of play–or anything close to it–for this long.

At the risk of belaboring the point, similar arguments can be made for 33-year-old Fed, all the way to 30-year-old Fed. At almost any stage in the last four years, Federer has been better than any player in history at that age [2].  Djokovic has matched many of Roger’s career accomplishments so far, especially on clay, but it would be truly remarkable if he maintained a similar level of play through the end of the decade.

Current Elo ratings

While it’s not really germane to today’s subject, I’ve got the numbers, so let’s take a look at the current ATP Elo ratings. Since Elo is new to most tennis fans, I’ve included columns to indicate each player’s chances of beating Djokovic and of beating the current #10, Milos Raonic, based on their rating. As a general rule, a 100-point gap translates to a 64% chance of winning for the favorite, a 200-point gap implies 76%, and a 500-point gap is equivalent to 95%.

Rank  Player                  Elo  Vs #1  Vs #10  
1     Novak Djokovic         2511      -     91%  
2     Roger Federer          2386    33%     84%  
3     Andy Murray            2332    26%     79%  
4     Kei Nishikori          2256    19%     71%  
5     Rafael Nadal           2256    19%     71%  
6     Stan Wawrinka          2186    13%     62%  
7     David Ferrer           2159    12%     58%  
8     Tomas Berdych          2148    11%     56%  
9     Richard Gasquet        2128    10%     54%  
10    Milos Raonic           2103     9%       -  
                                                  
Rank  Player                  Elo  Vs #1  Vs #10  
11    Gael Monfils           2084     8%     47%  
12    Jo-Wilfried Tsonga     2083     8%     47%  
13    Marin Cilic            2081     8%     47%  
14    Kevin Anderson         2074     7%     46%  
15    John Isner             2035     6%     40%  
16    David Goffin           2027     6%     39%  
17    Grigor Dimitrov        2021     6%     38%  
18    Gilles Simon           2005     5%     36%  
19    Jack Sock              1994     5%     35%  
20    Roberto Bautista Agut  1986     5%     34%  
                                                  
Rank  Player                  Elo  Vs #1  Vs #10  
21    Philipp Kohlschreiber  1982     5%     33%  
22    Tommy Robredo          1963     4%     31%  
23    Feliciano Lopez        1955     4%     30%  
24    Nick Kyrgios           1951     4%     29%  
25    Ivo Karlovic           1949     4%     29%  
26    Jeremy Chardy          1940     4%     28%  
27    Alexandr Dolgopolov    1940     4%     28%  
28    Bernard Tomic          1936     4%     28%  
29    Fernando Verdasco      1932     3%     27%  
30    Fabio Fognini          1925     3%     26%

Continue reading The Case for Novak Djokovic … and Roger Federer … and Rafael Nadal

The Dream of the Nineties is Alive

Last weekend, the four finalists in ATP events were David Goffin, Dominic Thiem, Vasek Pospisil, and Milos Raonic. All were born in the 1990s, making the Kitzbuhel and Washington finals the first all-nineties championship matches in tour history.

It’s about time. The first half of the 1990-born cohort is already 24 years old, an age that used to suggest a tennis player was approaching his prime. Of the four finalists, only Thiem wasn’t born in 1990. (He was born in 1993, making him the youngest finalist of the season so far.)

It has never taken so long for a single-year-or-younger group of ATP players to play each other in a final. For the thirty-one years between 1960 births and 1990 births, it has, on average, taken less than 21 years before youngsters in each cohort face off for a title. It took 24 years and seven months before the 1990 group–with the help of Thiem–finally reached this milestone.

Here are the breakthrough finals for each age group in five-year intervals, to put the 1990 group in perspective:

The age of these milestone finals has been steadily creeping up over the last few years. The class of 1987 was a good one, giving us Novak Djokovic and Andy Murray, but even those two stars didn’t meet in a final until the 2008 Cincinnati Masters, when both had passed their 21st birthdays.

There’s a sharp downturn after that 1987 class. The ATP didn’t see a 1988-or-younger final until three years later, when Alexandr Dolgopolov faced Marin Cilic in the 2011 Umag title match. In the three years since then, there have been only six more 1988-or-younger finals, including the two last weekend.

Thiem, along with a few other young players, offers hope that the tides are beginning to turn. This week, for the first time since 2005 (when, as we’ve seen, Nadal and Berdych played the last all-teenage final), the ATP top 200 features four teenagers, two of whom–Borna Coric and Alexander Zverev–are not yet 18. Then again, neither Goffin nor Pospisil reached a final until they had been inside the top 200 for three years. We may need to keep looking to 23-year-olds for ATP firsts.

Nick Kyrgios and the First Fifty Matches

When Nick Kyrgios lost the Wimbledon quarterfinal to Milos Raonic yesterday, he was playing his 50th career match at the Challenger level or above. Round numbers invite big-picture analysis, so let’s see how Kyrgios stacks up to the competition at this early milestone.

When Monday’s rankings are released, Nick will debut in the top 100, all way up to #66. Only Rafael Nadal (61), Gael Monfils (65), and Lleyton Hewitt (65) have been ranked higher at the time of their 51th Challenger-or-higher match.  Roger Federer was #93, Novak Djokovic was #128, and Jo Wilfried Tsonga was #314. Of the current top 100, only ten players reached a double-digit ranking by their 51st match.

The wealth of ranking points available at Grand Slams have played a big part in Kyrgios’s rise, but they don’t tell the whole story. He has won 36 of his first 50 matches, equal to the best of today’s top 100. Nadal went 36-14, and next on the list is Djokovic and Santiago Giraldo (who played almost all Challengers) at 34-16. Most of Nick’s wins before this week came at Challengers, and he has won four titles at the level.

No other active player won four Challenger titles in his first 50 matches. Eight others, including Djokovic, Tsonga, Stanislas Wawrinka, and David Ferrer, won three. All of them needed more events at the level to win three titles than Kyrgios did to win four.

Nick’s short Challenger career is another indicator of a bright future. He has only played nine Challenger events, and with his ranking in the 60s, he may never have to play one again. As I’ve previously written, the best players tend to race through this level: Federer, Nadal, and Djokovic all played between eight and twelve Challengers. It’s a rare prospect that makes the jump in fewer than 20 events, and when I researched that post two years ago, more than half of the top 100 had played at least 50 Challengers.

One category in which the Australian doesn’t particularly stand out is age. When he plays his 51st match, he’ll a couple of months past his 19th birthday. Roughly one-quarter of the current top 100 reached that match total at an earlier age. Nadal, Richard Gasquet, and Juan Martin del Potro did so before their 18th birthday, while Djokovic, Hewitt, and Bernard Tomic needed only a few more weeks beyond that.

Without knowing how Kyrgios would’ve performed on tour a year or two earlier, it’s tough to draw any conclusions. His 36-14 record at 19 certainly isn’t as impressive as Rafa’s equivalent record at 17.

Cracking the top 100 at 17 or 18 is a much better predictor of future greatness than doing so at 19, but as the tour ages, 19 may be the new 16. Grigor Dimitrov didn’t enter the top 100 until he was three months short of his 20th birthday, while Dominic Thiem and Jiri Vesely were still outside the top 100 on their 20th birthdays. Among his immediate cohort, Kyrgios stands alone: No other teenager is ranked within the top 240.

As predictive measures go, Nick’s Wimbledon performance–built on his poise under pressure–is the best sign of them all. Only seven active players have reached a Grand Slam quarterfinal as a teenager, and four of them–Fed, Rafa, Novak, and Lleyton–went on to reach #1. (The other three are Delpo, Tomic, and Ernests Gulbis.)

For a player with only fifty matches under his belt, that’s excellent company.

Teenagers, Thirty-Somethings, and Americans at Grand Slams

I’ve put together a few reports showing how age distributions and US presence have changed over the years at Grand Slams.  Let’s start with player age.

The average age of players in the Wimbledon men’s singles draw is 27.7 years, which is just short of the all-time record, 27.8, set at Roland Garros last month, and equal to last year’s figure at Wimbledon. There are two teens in the draw (up one from last year), and 34 thirty-somethings, which is tied for third-most since 1982.

This report shows the complete year-by-year breakdown for the last 30 years’ worth of men’s slam draws.

The average age in the Wimbledon women’s draw is also very high by historical standards.  At 25.2 years, it’s tied with this year’s French Open and 2012 Wimbledon for the highest ever.  43-year-old Kimiko Date Krumm moves the needle all by herself; without her, the average would be 25.0, still considerably higher than any other pre-2010 slam.

There are ten teenagers in the draw, which is very low for the WTA, but safely above the all-time low of 7, set at Wimbledon two years ago. The total of 16 players aged 30 or over is good for third-most of all time, behind this year’s and last year’s French Opens.

Here’s the WTA report showing these numbers for each slam in the last 30 years.

(All of the figures above for 2014 Wimbledon could change slightly if more lucky losers are added to the draw.)

I also put together a couple of reports showing the number of Americans in each slam draw, broken down by direct entrants, qualifiers, lucky losers, and wild cards, along with the top seed, the number of seeds (and top 16 seeds), plus the number of Americans in each round:

Enjoy!

 

Bouchard, Halep, and First-Time Quarterfinalists

Two of the final eight women in Melbourne, Eugenie Bouchard and Simona Halep, are playing in their first Grand Slam quarterfinals. Let’s take a look at how other women have done in their first appearances this late in a Slam.

In the Open era, 267 different women have reached the final eight of a Slam. At the time of their debut quarterfinal, their average age was roughly 21 years and four months. Their average WTA ranking was 42, not considering those who predated the ranking system or those who reached their first quarterfinal as an unranked player.

Of the 267, 197 (73.8%) progressed no further in their breakthrough slam. 52 (26.4%) won one more match, losing in the semifinals; 12 (6.1%) reached the final but lost; and the remaining six players won the title when the reached their first Open-era quarter.

However small 6 of 297 sounds, such an outcome is actually even rarer. Three of those six first-time quarterfinalists don’t really count–they reached their first QF in 1968, the first year of the Open era. Billie Jean King, winner of the Australian Open that year, isn’t that great a comp for Bouchard or Halep. The only other players to win a Grand Slam in their first quarterfinal appearance are Chris O’Neil (1978 Australian), Barbara Jordan (1980 Australian), and Serena Williams (1999 US Open).

While we can’t count on Bouchard or Halep winning the tournament this week, their appearances in Slam quarterfinals at relative young ages bodes well. The earlier a player reaches her first major QF, the more QFs she is likely to reach over the course of her career.  In fact, of the 22 women who have reached more than 10 Slam quarterfinals since 1984, only one of them–Jana Novotna–failed to reach her first one in her teens. She didn’t make it until the ripe old age of 20 years and 8 months.

Bouchard has just snuck in before her 20th birthday, which she’ll celebrate next month. Her most age-appropriate comp is Victoria Azarenka, who reached her first major quarterfinal–at the 2009 French Open–just a few weeks younger than Genie is now. Less than five years later, Vika will play her 12th Slam QF.

Less optimistic comparisons for Bouchard are Yanina Wickmayer and Anna Chakvetadze, both of whom reached their first major quarterfinal in the last two months of their teens. Chakvetadze made two more final eights; Wickmayer is still looking for her second.

If history is any guide, Halep’s prospects are bleaker. At 22 years and four months, she is much older than any of the players who have reached double-digit Slam quarterfinals except for Li Na, who is playing in her 10th QF this week. Li didn’t play in the final eight of a Grand Slam until she was 24 years old.

The 61 players who reached their first Slam QF at an older age than Halep did not, on average, achieve much more. They’ve totaled 81 additional QFs–well below two per person.

Of course, the age profile of the WTA is changing, so a 22-year-old debutante isn’t nearly the oddity it was a decade or two ago. It’s no coincidence that Halep’s most optimistic comp is Li, an active player. That’s the most positive outlook for the Romanian, anyway. To rack up an impressive career record, she’ll have to follow Li’s lead and overcome a late start.

The ATP final eight also features a newbie, Grigor Dimitrov. The changing age profile of the ATP is even more drastic, so age-based analysis is less meaningful. But we can take a quick look at the precedents for the Bulgarian’s first Slam quarterfinal.

There have been 329 ATP Slam quarterfinalists in the Open era, and first-timers stand a better chance in the men’s game. 32.5% of debut Slam quarterfinalists have advanced to the semis, and 13 of them (4.0%) went on to win the tournament. Then again, none of them had to beat Rafael Nadal in the quarters.

While Dimitrov is older than Halep–and as noted, 22-year-olds didn’t used to be considered so young on the ATP tour–there are some positive examples for Grigor to follow.

Michael Stich reached his first Slam QF at almost exactly the same age as Dimitrov is now, and he not only reached the semis at that event (the 1991 French Open), but qualified for the final eight in nine more majors. Jo Wilfried Tsonga, David Ferrer, and Nikolay Davydenko all reached their first Slam QF later than Dimitrov, and each has played in the final eight at least ten times.

On average, those optimistic comps are outweighed by all the guys who made it to one or two Slam QFs later in their career. The 153 players who reached their first final eight later than Dimitrov’s current age have returned to a total of 362 additional quarterfinals–good for one or two more appearances per player.

Despite all the hype, Dimitrov’s performance this year isn’t a drastic breakthrough. It’s only a single step in the right direction–especially considering that he reached this milestone by beating the #73 player in the world. He could be the next Tsonga, or he could be the next Robby Ginepri.

The Geriatric Australian Open

You’ve probably heard about the steady aging of professional tennis.  In both the men’s and women’s games, fewer teenagers than ever are winning important matches, and more and more thirty-somethings are remaining at the top of the game.

My favorite illustration: 25 years ago, the oldest man in the Australian Open draw was Johan Kriek, about two months short of his 31st birthday when the tournament began.  This year, 24 men in the main draw are older.

A total of 33 men in the singles draw have reached their fourth decade, only the third time in tournament history that the number has exceeded 20.  If lucky loser Stephane Robert replaces the injured Gilles Simon, we’ll have 34 thirty-somethings, tied with the all-time record, set in 2012.

Even without Simon’s withdrawal, we already have a record for average age in the men’s draw.  That figure this year is 27 years and 126 days, 80 days more than the previous record, set last year.  (Replacing Simon with Robert would add another 11 days to the average.) The new record also marks the seventh consecutive year that the average age of the men’s singles draw has increased.

While the age of the women’s draw isn’t quite record-setting, the rise of thirty-somethings in the women’s game has been even more rapid.  Only 13 years ago, in 2001, Els Callens was the only woman over the age of 30 in the draw (she was a mere 156 days past her 30th birthday).  This year, there are a record-high 15 players over the age of 30 in the women’s singles draw.

The 2012 Aussie Open field remains the oldest on record, at 24 years and 321 days.  This year’s draw–at 24 years and 292 days–is close enough that, had 16-year-old Ana Konjuh lost her third-round qualifying match to Olga Savchuk, ten years her senior, we would be looking at a new record.

Long term trends and the folly of forecasting

By just about any metric you might devise, the game has gotten steadily older for about 25 years.  As with any trend in the news, this one has led too many commentators–both casual and more academic–to claim that this is a permanent trend, or that “you’ll never see another teenage tennis champ.”

Protip: Never put your money on “never.”

What these arguments often fail to account for is that, for about twenty years after the inception of the pro game in the late 1960s, the sport–both men’s and women’s–consistently got younger.  When the 2012 Wimbledon men’s draw broke that event’s record for average age, the record it was breaking was from 1968.

Sure, there are plenty of possible explanations for the steady age decline of the 1970s and 1980s, just as there are many for the current increase.  And there are probably hard limits at either extreme that prevent the age of the game from swinging too far in either direction.

In any case, we’re not in the middle of an infinite rise in ages any more than we were amid an endless decline in 1985.  Twenty years from now, the 2014 Aussie Open data points could be an meaningless step on this upward path or an important inflection point in another shift in the game.  We’re unlikely to see a teenage Slam champ next year, or the year after that, but is it really possible to make a sensible case that, in six years, today’s 12-year-olds will be helpless against today’s 24-year-olds?

What we can be confident about is what has happened, and even without accounting for the return of Pat Rafter, this year’s Melbourne field represents yet another data point in the aging of elite-level tennis.

Detailed stats: Lots of great things are happening with the Match Charting Project. Several people have stepped forward and started contributing to the project already this year, and we’re up to 144 matches in the database.  From Day One in Australia: Bencic vs Date-Krumm, Venus vs Makarova, and Errani vs Goerges.  I hope you’ll join in the fun.

David Ferrer and Defiance of the Aging Curve (+Updated WTForecast)

At the end of 2009, aged 27, David Ferrer finished the year with an ATP ranking of 17.  It had been a rough 15 months.  A poor pair of Masters events at the end of 2008 knocked him out of the top five, all the way down to 12.  An indifferent season saw him fall out of the top 20 for a few weeks.  Many players never improve upon their mid-20’s form, so had things gone according to script, Ferrer might still be kicking around the high teens.  His near contemporaries Mikhail Youzhny and Tommy Robredo have followed paths of that nature.

Instead, the Spaniard has only gotten better.  He finished 2010 back in the top ten, at #7.  At the end of 2011 and 2012, he sat at #5.  He’s likely to conclude 2013 at his career-high position of #3.  All this at the age of 31, when many players have shifted focus to their golf games.

This is unprecedented.  Ferrer is only the 12th player of the last 30 years to string together four consecutive year-to-year ranking improvements starting at age 24 or later.  He’s only the second to do so starting at 27, and no one has done it from a more advanced age.  The only other man to match Ferru’s current streak doesn’t really compare: Wayne Arthurs improved his ranking from 1998 to 2002 up to an ’02 year-end position of #52.

Admittedly, this streak is a bit of a sideshow curiosity.  But the underlying issue it reveals is more significant.  Even in an era of 30-something stars on the ATP, tennis is a young man’s game.  At the age when Ferrer began his resurgence, most players are fading, if they’re not already gone.

The exact trajectory of the aging curve depends on the data you choose to examine.  I ran the numbers twice: first with all players in the top 300 since 1983, then limited to players born in 1975 or later.  With the bigger dataset, the apparent peak is at age 23-24.  The average player maintains their level from their age 23 season to their age 24 season, but every year beyond 24 brings with it an increasing decline.  For instance, if we set aside those who disappear from the top 300 entirely, 45% of players improve their ranking in their age 25 season, while 2% maintain it and 53% decline.  At age 26, it’s 38%, 2%, and 60%, while at age 31, it’s 30%, 1%, and 69%.

The following graph shows the percentage of players who improve and decline in the rankings at each age.  While there are still a few guys like Ferrer who post a year-to-year improvement at any age, they are harder to find at each successive age.  Also, keep in mind that the later-career numbers include players returning from injury–Lleyton Hewitt, for example, has improved his ranking each of the last two years.

ferru2

Limiting our view to those players born in 1975 or later, we have a smaller dataset, but one that should better reflect the current state of affairs.  Here, the peak is one year later, at age 24-25.  Despite the Ferrers, Roger Federers, and Radek Stepaneks who seem to be rewriting the rules, it is still the case that only 42% of 26-year-olds improve their rankings from their age 25 season, while 3% maintain and 55% decline.

Another way of looking at the decline is by measuring and then aggregating the magnitude of ranking changes.  In the dataset limited to 1975-and-later births, he average player loses roughly 2.5% of his ranking from his age 25 season to his age 26 season, and almost 19% of his ranking from age 31 to age 32.  Using this metric, here is a graph of two “decline curves”–ranking position lost at each age.  Both the overall dataset and the more limited, recent dataset are shown:

ferru3

While the overall direction hasn’t changed from the 80s to the present, the trend in magnitude is clear. At every age in the decline phase, the curve has flattened out, making it a bit more likely that someone like Ferrer would improve throughout his late 20s.

Keep in mind that we’re only measuring those players who remain in the top 300.  Those who retire or fall out of the rankings due to injury aren’t considered, so the actual effect of age–in either dataset–is more severe than these numbers represent.  However, without forcing those guys to play, we can only estimate their aging patterns based on those who do stick around.

Having determined the percentages of players in the current era who improve and maintain their rankings at each age, we can calculate the likelihood that someone would do what Ferrer has done, keeping his ranking moving in the right direction from his age 27 to his age 31 season.  For any individual year, the chances are about 40%, giving us an overall probability of roughly 2.5%, or 1 in 40.  Even limiting our scope to the pool of players in the ATP top 300 at age 27, that seems reasonable–Ferru is, at the very least, a 1-in-40 aberration.

Ferrer’s biggest test yet will be his age-32 season in 2014.  Of players in the current era, 18% of 31-year-olds fall out of the top 300 by the end of their age-32 season.  (In the bigger dataset going back to 1983, 27% disappear.)  Of those who remain, only a quarter improve, and the average ranking change is strongly negative.

Eventually, nature will stop David Ferrer.  Precedents or no precedents, though, he’s a hard man to bet against.  He hasn’t been particularly constrained by nature thus far.

London forecast: After today’s Group B matches, Djokovic is guaranteed a spot in the semis, while Federer’s match on Saturday with del Potro will determine the other semifinalist.  My ratings consider those to be nearly equal on this surface, giving the slight edge to Delpo.  Here is the complete forecast:

Player     3-0  2-1  1-2  0-3        SF      F      W  
Nadal      70%  30%   0%   0%     98.5%  57.9%  33.3%  
Djokovic   73%  27%   0%   0%    100.0%  65.8%  36.3%  
Ferrer      0%   0%  54%  46%     14.7%   5.1%   1.9%  
Del Potro   0%  52%  48%   0%     52.3%  23.3%  10.7%  
Federer     0%  48%  52%   0%     47.7%  20.1%   8.8%  
Berdych     0%  30%  70%   0%     35.8%  11.9%   3.9%  
Wawrinka    0%  46%  54%   0%     51.1%  16.0%   5.2%  
Gasquet     0%   0%  27%  73%      0.0%   0.0%   0.0%

My algorithm doesn’t capture all the complexity of the tiebreak rules, so it’s got Group A a bit wrong right now.  Nadal has locked up a spot in the semis. To clear up any remaining confusion, we’re lucky to have Anna, who lays out the qualification scenarios very clearly for both Group A and Group B.

Today’s matches: I charted both Group B matches today, so there are detailed serve, return, and shot-by-shot stats for each one.  Here is Federer-Gasquet, and here’s Djokovic-del Potro.

Finally, it’s already time to look ahead to Melbourne, as Foot Soldiers of Tennis is monitoring the players on the cusp of direct entry.