Visualizations of the First Day of Round 4 at the 2016 U.S. Open

05 Sep 2016

Day 7, the last day of week 1 at the 2016 U.S. Open, saw the losses of two Americans (Keys and Sock), the upset of a favorite for the men’s title (Nadal), and the resurgence of a former World No. 1 (Wozniacki). Below are the point-by-point win prediction charts for 4 of the most interesting wins in the first half of Round 4.

Woz Cruises

With the losses and injury struggles Caroline Wozniacki has dealt with this season, she was the low-probability bet going into her fourth round match against American Madison Keys. FiveThiryEight predictions gave Wozniacki only a 33% chance of taking the match. The Dane appeared to have no interest in what these numbers had to say, though, when she got the first break in the fourth game of the first set. That achievement put the odds at an even draw.

Wozniacki continued to add to the pressure on Keys in the sixth game, creating 2 more break chances. Wozniacki didn’t convert, however, but she didn’t need to. Both players held serve for the remainder of the set giving Wozniacki the first set.

With the first set in the bag, Woz went into the second set with a 70% chance of taking the match. That rose to 80% when she earned a break in the first game. Keys threatened a comeback in the fourth game when she won the break back only to broken in the next game. At that point, Wozniacki’s win probability was at 90% and her spot in the quaterfinals secured.

Sevastova's Roll Continues

Like Wozniacki, Anastasija Sevastova was the underdog in her Round 4 match against Johanna Konta. With just a 31% expected chance of winning the match, Sevastova also tried to pounce on Konta’s serve early. However, Konta was going to make it more of a struggle than Keys managed against Wozniacki. Over 2 sets, Konta and Sevastova had 12 breaks of serve. Sevastova managed to edge out Konta by 1 break in both sets, taking the win and avoiding a tiebreak in each case. The key turning points in Sevastova’s win was the break in the eighth game of the first set, bringing her win chance to 50%, and the break in the fourth game of the second, which boosted her win chances to 80%.

Tsonga Threatened But Not Defeated

Jo-Wilfried Tsonga was the clear favorite against USA’s own Jack Sock. Tsonga’s win chances were at 61% at the start of the match and rose to 75% when he took the first set. By the end of the second set, having faced only 2 break points and saved both, it looked like it was the all-Jo show. At the start of the third set, Tsonga’s win chance was at a high of 90%.

With his back against the wall, Sock began to make move in the third game of the third set, winning the first break of the set. Tsonga won that break back in the sixth game, which eventually forced a tiebreak which Sock took in 16 tightly contested points.

Still, with two sets on the board, Sock would have to do more to turn the odds against Tsonga. Things looked like they might swing in Sock’s favor when he got to 30 in the second game. But Tsonga took the upperhand, converting 2 of 2 break points in his subsequent return games. In the end, Tsonga won having been pushed but not exhausted, which could be the best preparation for the quarters he could have hoped for.

Unstoppable Pouille

The most unlikely win of the fourth round had to be Lucas Pouille’s victory over an in-form Rafael Nadal. The forecast for Pouille’s chances of overcoming the Spaniard were just 14%. It was going to take a strong lead to overcome that deficit. Pouille sent out the message that he wasn’t going to take his ticket home easily when he won the first set at 6-1. Still, even the set on the board only increased his chances to 30%. The odds went against him again when Nadal took the second but Pouille found away to win the third. The major turning points in the third set were the early break Pouille won in the first game and fighting off break points on his serve in the fourth game.

Fascinatingly enough, even with 2 sets secured Pouille was still just below 50% for the win, Nadal still being the strong favorite on serve and return.

Pouille appeared to have lost belief starting with the break point in the fourth game of the fourth set and the eventual break of his serve in the sixth game. Things got really rocky from that point on as Pouille lost the fourth set and was broken immediately in his first service game of the deciding set. By the seventh game, Pouille’s odds of pulling out an upset had hit a low of 5%. With the end of the set approaching, Pouille somehow worked a mental miracle in the eighth game by winning a break back. That would turn out to leave it all to the tiebreak.

Even at that point, the probabilities didn’t believe Pouille could do it. After losing the first point, Pouille had to win 4 points straight to get the stats on his side. At that point, he was a 50% favorite and he, in one of the most impressive battles of the Open, fought to hold that advantage and take the win.

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