{"id":2949,"date":"2018-09-03T15:56:34","date_gmt":"2018-09-03T15:56:34","guid":{"rendered":"http:\/\/www.tennisabstract.com\/blog\/?p=2949"},"modified":"2018-09-03T15:56:34","modified_gmt":"2018-09-03T15:56:34","slug":"two-servebots-and-zero-tiebreaks","status":"publish","type":"post","link":"https:\/\/www.tennisabstract.com\/blog\/2018\/09\/03\/two-servebots-and-zero-tiebreaks\/","title":{"rendered":"Two Servebots and Zero Tiebreaks"},"content":{"rendered":"<p><a id=\"FIJJ8lq5Tw9olAFEpOYY_A\" class=\"gie-single\" style=\"color: #a7a7a7; text-decoration: none; font-weight: normal !important; border: none; display: inline-block;\" href=\"http:\/\/www.gettyimages.no\/detail\/1026327640\" target=\"_blank\" rel=\"noopener\">Embed from Getty Images<\/a><script>window.gie=window.gie||function(c){(gie.q=gie.q||[]).push(c)};gie(function(){gie.widgets.load({id:'FIJJ8lq5Tw9olAFEpOYY_A',sig:'QngA-nQp2YH9H6_Kigijfr4dOIB75spuaGU-oVkslPw=',w:'594px',h:'396px',items:'1026327640',caption: true ,tld:'no',is360: false })});<\/script><script src='\/\/embed-cdn.gettyimages.com\/widgets.js' charset='utf-8' async><\/script><\/p>\n<p><em>Isner had energy to burn since he never needed to count to seven.<\/em><\/p>\n<p><a href=\"http:\/\/www.tennisabstract.com\/settesei\/2018\/09\/05\/due-macchine-da-servizi-zero-tiebreak\/\"><em>Italian translation at settesei.it<\/em><\/a><\/p>\n<p>There have been plenty of upsets at this year&#8217;s US Open, but they all pale in comparison with the surprise that <a href=\"http:\/\/www.tennisabstract.com\/cgi-bin\/player.cgi?p=JohnIsner\" target=\"_blank\" rel=\"noopener\">John Isner<\/a> and <a href=\"http:\/\/www.tennisabstract.com\/cgi-bin\/player.cgi?p=MilosRaonic\" target=\"_blank\" rel=\"noopener\">Milos Raonic<\/a> delivered Sunday night in their fourth round match. Isner won, 3-6 6-3 6-4 3-6 6-2, <a href=\"https:\/\/www.usopen.org\/en_US\/scores\/stats\/1404.html\">failing to hold twice<\/a> and breaking Raonic&#8217;s serve four times. Rarely has a tiebreak seemed so assured, and the two big men didn&#8217;t even get close.<\/p>\n<p>In five previous meetings, Isner and Raonic have been more likely to deliver\u00a0<em>two<\/em> tiebreaks than only one, and most of their matches were best-of-three, not the grand slam best-of-five format. In 13 previous sets, they had played 9 tiebreaks. In the last year, 45% of Isner&#8217;s sets have reached 6-6, while nearly a quarter of the Canadian&#8217;s have. One or the other of these guys is responsible for the longest match in history, the longest ever major semi-final, and the longest match in Olympics history. They are really, really good at holding serve, and really not-so-good at breaking.<\/p>\n<p><strong>Great expectations<\/strong><\/p>\n<p>The likelihood that Isner and Raonic would play a tiebreak depends on some basic assumptions. If Raonic served like he has for the last 52 weeks, that&#8217;s a service-point won percentage (SPW) of 72.8%, which is equivalent to holding 93% of the time. If we use Isner&#8217;s actual SPW from the match of 74.3%, that translates to a hold rate of 94.4%. If we choose Isner&#8217;s SPW from his previous meetings with Raonic of a whopping 76.5%, that gives us an implied hold rate of 96%. Those all sound high but, as we&#8217;ll see, the difference between them ends up affecting the probability quite a bit.<\/p>\n<p>I&#8217;m going to run the numbers using three sets of assumptions:<\/p>\n<ol>\n<li><em>The head-to-head.\u00a0<\/em>In five matches (four of them on hard courts, the fifth at Wimbledon this year), Isner won 76.5% of service points, while Raonic won 71.4%. That&#8217;s equivalent to hold rates of 96.0% and 91.7%, respectively.<\/li>\n<li><em>The last 52 weeks (adjusted).\u00a0<\/em>Across all surfaces, going back to last year&#8217;s US Open, Isner has won 73.6% of service points, against Raonic&#8217;s 72.8%. Those numbers, however, are against average opponents. Both players, and especially Isner, have below-par return games. If we adjust each SPWs for the other player&#8217;s rate of return points won (RPW), we get 75.5% for Isner and 78.5% for Raonic. In game-level terms, those are hold rates of 95.3% and 97.1%.<\/li>\n<li><em>The match itself<\/em>. On Sunday night, Isner won 74.3% of service points and Raonic won 68.8%. Using these numbers doesn&#8217;t give us a true prediction, since we couldn&#8217;t have known them ahead of time. But maybe, if we used every scrap of information available to us and put them all together in a really smart way, we could have gotten close to the true number. Those rates translate to hold percentages of 94.4% for Isner and 88.5% for Raonic.<\/li>\n<\/ol>\n<p><strong>Not enough tiebreaks<\/strong><\/p>\n<p>Apparently, the betting odds for at least one tiebreak in the match set the probability <a href=\"https:\/\/twitter.com\/baselinebetting\/status\/1036494893231886337\">around 95%<\/a>. That turns out to be in line with my predictions, though the specific assumptions affect the result quite a bit.<\/p>\n<p>I&#8217;ve calculated a few likelihoods using each set of assumptions. The first, &#8220;p(No brk),&#8221; is the probability that the two men would simply hold serve for 12 games. It&#8217;s not the only way to reach a tiebreak, but it accounts for most of the possibilities. Next, &#8220;p(TB)&#8221; is the result of a Monte Carlo simulation to show the odds that any given set would result in a tiebreak. &#8220;eTB&#8221; is the expected number of tiebreaks if we knew that Isner and Raonic would play five sets. Finally, &#8220;p(1+ TB)&#8221; is the chance that the match would have at least one tiebreak in five sets.<\/p>\n<pre>Model   JI Hld  MR Hld  p(No brk)   p(TB)   eTB  p(1+ TB)  \nH2H      96.0%   91.7%      46.5%   51.3%   2.6     97.3%  \nLast52   95.3%   97.1%      62.8%   65.3%   3.3     99.5%  \nMatch    94.4%   88.5%      34.0%   41.2%   2.1     93.0%<\/pre>\n<p>Given how the big men played on Sunday, it isn&#8217;t unthinkable that they never got to 6-6. In large part because Isner&#8217;s return game brought Raonic&#8217;s SPW under 70%, each set had &#8220;only&#8221; a 41.2% chance of going to a tiebreak, and there was a 7% chance that a five-setter would have none. The other two sets of assumptions, though, point to the sort of tiebreak certainty reflected in the betting market &#8230; and just about anyone who has ever seen these two guys play tennis.<\/p>\n<p>Perhaps the strangest aspect of all of this is that, in six previous matches at this year&#8217;s Open, Isner and Raonic combined for seven tiebreaks&#8211;at least one in five of their six matches&#8211;before their anticlimactic encounter. Knowing Isner, this is a blip, not a trend, and he&#8217;s sure to give us a breaker or two in his quarter-final against <a href=\"http:\/\/www.tennisabstract.com\/cgi-bin\/player.cgi?p=JuanMartin\" target=\"_blank\" rel=\"noopener\">Juan Martin<\/a><a href=\"http:\/\/www.tennisabstract.com\/cgi-bin\/player.cgi?p=JuanMartinDelPotro\" target=\"_blank\" rel=\"noopener\"> del Potro<\/a>. His tournament record will likely show one or two tiebreaks in every match &#8230; except for the one against his fellow servebot. This must be why we stick with tennis: Every match has the potential to surprise us, even if we never really wanted to watch it.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Embed from Getty Images Isner had energy to burn since he never needed to count to seven. Italian translation at settesei.it There have been plenty of upsets at this year&#8217;s US Open, but they all pale in comparison with the surprise that John Isner and Milos Raonic delivered Sunday night in their fourth round match. &hellip; <a href=\"https:\/\/www.tennisabstract.com\/blog\/2018\/09\/03\/two-servebots-and-zero-tiebreaks\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Two Servebots and Zero Tiebreaks<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[40,105,114],"tags":[],"class_list":["post-2949","post","type-post","status-publish","format-standard","hentry","category-forecasting","category-serve-statistics","category-tiebreaks"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts\/2949","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/comments?post=2949"}],"version-history":[{"count":0,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/posts\/2949\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/media?parent=2949"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/categories?post=2949"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tennisabstract.com\/blog\/wp-json\/wp\/v2\/tags?post=2949"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}