Alarming Coco Gauff service stats highlight why she made big coaching change

Oli Dickson Jefford 26 Aug 2025 1:30 PM

Coco Gauff hits a serve in practice.

Coco Gauff’s US Open campaign gets underway on Tuesday night, and the build-up to her round-one match has been dominated by one huge talking point.

It was confirmed last week that Gauff had split with coach Matt Daly after an 11-month partnership, the pair parting ways with just a week until the final major tournament of 2025.

Changing coaches just days before a Grand Slam is not a move that many would even consider, but past coaching alterations have worked for the 21-year-old in the past.

And, with new coach Gavin MacMillan having previously fixed Aryna Sabalenka’s serving struggles, she may have found the right person to banish her own service woes once and for all.

Gauff’s partnership with Daly, which began after the US Open last year, should ultimately be considered a success.

The American won her second Grand Slam singles title at the French Open this spring, and triumphed at the China Open and WTA Finals at the tail end of 2024.

However, when you dig further into her service numbers, the reason for Gauff’s sudden decision becomes more than clear.

Alarming statistics

No woman served more double faults than Gauff on the WTA Tour last year, and the American looks set to top that unfortunate list once again in 2025.

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The American has hit a staggering 320 double faults in 2025, heading into the start of her US Open campaign, an average of 6.8 double faults across her 47 matches so far this season.

While that may not sound too alarming on paper, it stands out significantly across the rest of the WTA field.

Gauff has served 95 more double faults than Alycia Parks (225), who sits in second place in the double fault standings this season.

In third place, Ekaterina Alexandrova (215) is 105 behind, with Jelena Ostapenko (211) 109 double faults behind in fourth.

In contrast to Gauff, world No 1 Sabalenka has served just 122 double faults across 61 matches this year, an average of just two double faults per match.

Meanwhile, world No 2 Iga Swiatek has served 175 double faults ahead of action in New York, an average of 2.87 per match this season.

Sabalenka has an impressive 217 aces compared to her 122 double faults, while Swiatek’s 180 aces are just ahead of her 175 double faults.

However, Gauff has served only 138 aces this year, giving her a -182 differential in aces to double faults this season.

Compared to her two main rivals, Gauff’s first serve and first serve points win percentage are pretty level at the top of the game.

The American has landed 60% of first serves in play this season, and has won 69.5% of those points.

Sabalenka has a 62.4% first-serve percentage for 2025, and her 68% of points won is slightly less than Gauff, with Swiatek holding a 62% first-serve percentage and a 69.3% points won record for 2025.

However, while she is narrowly ahead of both Sabalenka and Swiatek in terms of first serve points won, her second-serve stats are alarming.

The world No 3 has won just 42.7% points on her second serve in 2025, compared to 50.5% for Sabalenka and 50.3% for Swiatek.

Gauff has also held in 68.7% of her service games, which puts her considerably behind Sabalenka on 76.6% and Swiatek on an impressive 78.1%.

The fact that Gauff has been able to win as much as she has in recent months and remain high in the WTA Rankings is a testament to how strong other areas in her game are.

However, there can be no denying that a huge improvement is needed in regards to serving, with this proving an obvious weakness in her game.

If the 21-year-old can fix her service struggles, you would think she could achieve even greater success than she already has.