Gauff’s serve has been a persistent issue this season. In recent tournaments, including the Montreal and Cincinnati Opens, she registered double-digit double faults per match—23 in one Montreal round and 16 in a Cincinnati quarterfinal loss to Jasmine Paolini. These struggles have contributed to her WTA-leading total of 320 double faults across 48 matches, averaging nearly seven per match.
After a team meeting and the departure of grip expert Matt Daly, Gauff brought in MacMillan in hopes of quickly improving her serve. “It was a sudden decision,” Gauff told reporters. “Gavin became available, and I felt this was the best decision for my game. I know Gavin has had experience with this before, so I’m hoping to take on his knowledge and see what can happen.”
MacMillan previously helped Sabalenka address technical flaws in her service motion, particularly issues with her left arm dropping and affecting accuracy. The changes led to a dramatic reduction in double faults for Sabalenka, improving her consistency on serve and boosting her confidence. Sabalenka praised MacMillan’s approach and expressed hope for Gauff’s progress: “I wish [Gauff and MacMillan] the very best, and hopefully everything can work out well for them.”
Gauff, a two-time Grand Slam champion and former US Open winner, is no stranger to making bold coaching changes. Last year, a switch to veteran coach Brad Gilbert propelled her to the US Open title. Later, bringing in Daly sparked a successful run through the Asian swing, culminating in a WTA Finals title in Riyadh. Now, with the US Open beginning Sunday and Gauff set to open against Ajla Tomljanovic at Arthur Ashe Stadium, the 21-year-old is looking for another breakthrough.
As Coco Gauff continues to chase greater consistency, tennis analyst Darren Cahill commented, “This could be a really good relationship.” Gauff herself remains focused on long-term improvement: “I know I needed to make a change, a technical change, and I don’t want to waste time continuing doing the wrong things. I’m obsessed with the process of getting better.”
The 2025 US Open promises to be a pivotal test for Gauff’s new partnership with MacMillan. With top players like Carlos Alcaraz, Jannik Sinner, and Iga Swiatek in the draw, the tournament is set to deliver high drama as Gauff seeks to overcome her serving woes and contend for another major title. For the latest updates and player stats, visit the official WTA profile and ESPN Tennis.