Caroline Wozniacki’s incredibly strict serving pattern is no secret — and it works

NEW YORK — At the US Open on Saturday, Caroline Wozniacki stepped to the baseline for her opening service game. Then she did what she almost always does.

On the first point of her match with Jessika Ponchet, Wozniacki served wide to her opponent’s forehand. On the next two points, she hit her serve along the center line, or the “T.” On the fourth point, she went wide to the ad court. Wide, T, T, wide.

It’s a pattern Wozniacki, remarkably, has repeated with little deviation for several years now. When her first serve misses its intended target, it’s less rigid — she can change the direction of the serve — but on the first serve, for the first four points of each game, the pattern is often the same.

When a game goes beyond four points, Wozniacki shifts to something seemingly more random. According to a 2019 analysis by TennisAbstract.com, she stays true to her plans about 80 percent of the time.

Against Nao Hibino in round one in New York on Tuesday, Wozniacki made only one change from her first-set routine, aiming for the body on the second point at 4-0. In the second set, she made only two clear switch-ups. Hibino, who had never played Wozniacki before, was crushed 6-0, 6-1.

In the second round, against Renata Zarazua, she made only two clear changes in the first set. Against Ponchet in round three, she made only four deviations in the first set. In the opening game of the second, she changed it completely, to TWWT, but she quickly returned to the plan, with only one exception.

At Wimbledon this year, it was much the same story. In her first-round win over Alycia Parks, Wozniacki went wide-TT-wide on the first four points every time in the first set. Against Leylah Fernandez in round two, she changed only once in the first set. There were more changes in sets two and three, but even then she stuck to the blueprint for the first four points 28 out of 40 times. In her 15 service games, her first serve was hit wide 14 times.

Perhaps Elena Rybakina got the message in the third round, when she defeated Wozniacki 6-0, 6-1. The former world No. 1 was outclassed in the first set when she deflected four times, but in the second set she turned things around, but to no avail.

In an age of readily available data, Wozniacki’s patterns are easy to spot for her opponents and especially their coaches. The 34-year-old declined requests from ESPN to discuss her thoughts, but she doesn’t seem concerned about players knowing where she’s going to serve. In three matches so far this year, she’s lost just 12 games.

Wozniacki advances to the fourth round for the second year in a row, playing either 15th-seeded Anna Kalinskaya or 22nd-seeded Beatriz Haddad Maia. She looks set to save her best form for the Grand Slams.

Many of those who have coached against Wozniacki know the pattern, or at least some of it. Mike James, a renowned data analyst on the tour, said he thinks most of the leading coaches on the WTA Tour should know it by now.

“Nowadays you have so many different ways to find serve patterns,” he said. “There are a lot of private companies that provide analysis, plus analysts that use the WTA/ATP Grand Slam data. Everyone should be doing their homework on serve patterns these days.”

It is to Wozniacki’s credit, then, that she has been so successful even when her intentions were so clear. James, who previously worked with Iga Swiatek and helped Coco Gauff and Victoria Azarenka at the US Open, says part of that is because direction isn’t the only thing a returner should focus on.

“Players often go to what’s comfortable when they’re uncomfortable, so I can understand (why Wozniacki does what she does),” he said. “If it’s comfortable enough, where they’re winning enough, why change it? It comes down to the quality of the ball. If the quality of the ball and the accuracy are good, keep doing it.”

Wozniacki returned to the sport in 2023 after a three-year absence during which she had two children. She was the world No. 1 in the year-end rankings for two consecutive years, in 2010 and 2011, and won a total of 30 titles, plus the Australian Open in 2018. Even then, in an epic three-set final with Simona Halep, she largely followed the pattern.

At first glance, knowing where an opponent is likely to serve should be a big advantage for the receiver. But maybe it’s just pragmatism on Wozniacki’s part. The serve has never been the strongest part of her game, so if that’s what makes her comfortable, then that’s fine. With her excellent movement and a brilliant backhand, she’s setting herself up to win the point no matter what.

Why wouldn’t a player change a clear pattern? “(Because) they’re really good at it and they trust it,” said Craig O’Shannessy, a strategy coach and analyst for ATPTour.com. “When things get tight and nervous, they know they can make that serve.”

O’Shannessy uses eight filters to show in detail what players are doing when they serve. He shows what the opponent thinks they are going to do, where the server wants the ball to come back, what the score is or under what conditions the match is being played.

“Sometimes you could even tell the opponent that I’m serving wide because it’s my highest percentage pattern or favorite pattern,” he said. “If you see enough of those filters coming at you, it helps you and it doesn’t matter what they know.”

And even if a player knows where the ball is likely to go, that doesn’t guarantee success. “The last thing you want is a player to turn around and say, ‘Hey, you said he was going to serve there,'” he added.

“I would present it like this: ‘This is where he wants to go.’ I coached a player here at Ashe against Roger Federer. I told him, ‘He likes to go wide, look forward to it.’ First point of the match, Fed goes all the way down the middle and the guy looks at me and stands there (with his arms wide open) for about five seconds. The match was over in his mind.”