Coco Gauff of United States celebrates while playing Lucia Bronzetti of Italy during the Cincinnati Open at Lindner Family Tennis Center on August 14, 2025 in Mason, Ohio. Matthew Stockman/Getty Images/AFP
NEW YORK— Coco Gauff was as aware as anyone, of course, that her tour-worst double-fault total is a significant problem, so she fired one of her coaches on the eve of the U.S. Open and brought aboard the serve doctor who helped No. 1-ranked Aryna Sabalenka work on her issues with that part of the game.
“I do know I needed to make a change — technical change — to it, and I don’t want to waste time continuing doing the wrong things,” Gauff said Friday at Flushing Meadows, where she won the first of her two Grand Slam titles in 2023.
READ: Coco Gauff overcomes 23 double-faults for first win since French Open
The year’s last major tournament begins Sunday.
“I know where I want to see my game in the future,” the 21-year-old American said. “I’m not going to waste time playing the way I don’t want to play.”
So she hired Gavin MacMillan, a biomechanics coach credited with rebuilding Sabalenka’s serving motion in 2022.
The next year, Sabalenka won her first major championship, then followed with two more, including at the 2024 U.S. Open. She’s back in New York as the defending champion and has been atop the WTA rankings for more than a year; the serve is now a key element in her success.
READ: Coco Gauff ‘tired of talking’ about Sabalenka French Open spat
“I tried literally everything, and nothing would help me to fix my serve. It was the last step before I would say, ‘OK, bye-bye, tennis.’ I was so desperate, so I wasn’t really doubting my decision,” Sabalenka said Friday about teaming up with MacMillan. “The moment we started working, I felt like, ‘OK, there is something. I definitely have a better feeling on my serve.’ And I just trusted the process, trusted myself. Like, the first tournament I played, I already felt the difference, and I felt, ‘OK, I’m getting there.’ So for me, it was just about repetitions, a little bit of time and full commitment to whatever he was saying.”
Gauff’s 320 double-faults this season not only are the most in the WTA, they’re more than 100 more than anyone else.
She’s averaging 6.8 per match and has accumulated them in big bunches, including 23 in a victory over Danielle Collins in Montreal this month, which was followed by 14 in her next match there, also a win.
Gauff hit another 16 double-faults in her loss to Jasmine Paolini at the Cincinnati Open last week.
At the U.S. Open 12 months ago, Gauff’s title defense ended with 19 double-faults in a fourth-round loss to Emma Navarro. Soon afterward, Gauff split from one of her coaches, Brad Gilbert, and added Matthew Daly to the team. Now Daly is gone.
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“I just want to get better. I’m obsessed with the process of getting better. Sometimes, maybe it hurts, because I get obsessed with it too much,” Gauff said. “I feel like I have a clear future where I see myself and I feel like I’m really close. I think this aspect of the game will bring everything together for me.”
