In yesterday’s morning recap, I made the following comment about Nadal’s baseline game:
The one baffling thing is Nadal’s reluctance to come to net. He was often standing right on the baseline, even hitting groundstrokes from a step inside the baseline. Yet he almost never came forward unless forced. Even with an imperfect net game, even against the passing-shot machine that is Djokovic, I think he would’ve been more successful taking advantage of some of those offensive positions.
In the comments, Tom Welsh laid out the flip side of the argument concisely:
During the Nadal-Djokovic match yesterday I noticed several occasions when each of those brilliant players came in to the net and was left looking like a hopeless beginner – either by a passing shot, or a sizzling ground stroke to the short ribs, or by a perfect lob landing just a couple of feet inside the baseline. I’m not tennis player, but it seems to me that no one can afford to come in these days unless the opponent is stretched to the breaking point. Even then, it’s taking a big risk.
That’s the argument in a nutshell. Even more briefly:
- PRO: Players should be more aggressive and come forward more often.
- CON: In the modern-day game, approaching the net is usually too risky.
Which is it?
Pick your poison
The first thing that needs to be understood is that, against an elite tennis player, anything is a risk. Short of a decisive smash, any shot you hit is likely to come back, and there’s a non-zero chance that what comes back is going to be a winner. Choosing to come forward isn’t a decision between risk and no risk, it’s a matter of degree.
The main difference is that, if you come forward and fail, you’ll look like a fool, and your opponent will look brilliant, in the ways Tom described. If you stay back and fail, it’s somehow more understandable–in a 15-stroke rally between top players, somebody has to lose. Of course, you lose the point either way.
One of the problems of arguing this point with anecdotal evidence is that I think we, as both fans and players, remember the brilliant passing shots and jaw-dropping lobs. If you rush the net and your opponent misses what would’ve been a sensational running forehand, you remember the amazing shot-that-almost-was. Human brains don’t default to probabilistic calculations, while brilliant moments catch and keep our attention.
Commentators, steeped in strategy of the 70’s and 80’s, will always want too much net-rushing. Most players will tend to stay back too much. If we can ever establish the proper opportunities to come forward, the “correct” answer will turn out to be somewhere in between.
Where the stats fail
Answering the question analytically will be very difficult, and given the information currently out there, it’s flat-out impossible.
In the meantime, let’s think through what it would take to answer the question. Starting with what I take to be the question itself:
Given his skillset, his opponent’s skillset, and each player’s position on the court, when should a player come forward?
That’s a lot of stuff we can’t quantify. Even if we posit a couple of generic pro players, it’s still an unanswerable question.
Particularly useless are existing net stats. Occasionally during a match, a broadcast will show us that so-and-so has won 5 out of 8 points at net. The commentators reliably chime in, usually suggesting that the player has better net skills that we give him credit for (perhaps he’s been playing some doubles lately), and that he would benefit by coming in more.
In most cases, those 8 points couldn’t be less relevant. Think back to Sunday’s Nadal-Djokovic match. Much of the time Nadal came forward, it was in response to a Djokovic drop shot. In other words, Nadal came forward on the defense! I’m guessing he lost most of those points. On the flip side, imagine Del Potro cracking a serve out wide, then coming in behind it to hit a swinging volley winner. That’s 1-for-1 on the net point tally, but it doesn’t say a thing about Delpo’s deftness of touch around the net.
Let’s imagine that we suddenly had access to Hawkeye’s shot-by-shot data. We’d know the hit point for every ball of every point of every match where the Hawkeye system was installed. (Drool.)
If we knew that, we could come up with a fairly simple model to estimate the likelihood of winning a point from any position on the court, against a certain quality of shot. Standing at the middle of the baseline smacking a 60 mph service return, you might have a 70% chance of winning the point. Stuck in the backhand corner after your opponent has cracked a 90mph groundstroke, and it might be more like 20%.
The details of the model aren’t important. What matters is that, with a certain data set, we could estimate the probability of winning a point given a variety of conditions.
Extending this framework to analyze a tactic like net-rushing wouldn’t be that complicated. Let’s say Nadal is standing on the baseline with a 70% chance of winning the point. No matter what he does afterward, he will probably hit a forehand into one corner or the other, after which we can once again estimate his probability of winning the point. From there, he has two choices: Come forward, or stay back. Some game theory might get involved, since his opponent will probably see him approach the net and may change his own strategy accordingly.
Again, we can work out the details when there is data to play with. Given these relatively simple figures, we could estimate Nadal’s probability of winning the point coming forward behind his forehand and staying back after hitting the shot.
The numbers would give a better way of judging whether a particular play is advisable. For Nadal, it may turn out that staying back is always smarter–after all, the numbers will probably tell us that, from any given position, he has a better chance than nearly anyone else of winning the point. But, say, Ivo Karlovic may be better off coming in behind the exact same shot from the same position. There’s a continuum between the extremes, of course, and we’ll need to know a lot more before we know what that looks like.
In the meantime, I’d still like to see Nadal come forward–and I’ll try harder to remember the times when his opponent goes for a blistering passing shot and misses.