As Coco Gauff prepares to challenge for her second US Open title, she has made some changes to her team to improve her chances. Gauff parted ways with her former coach, Matt Daly, just days before the tournament started, and she is already getting to work alongside the newest addition to her team.
Coco Gauff Spotted With New Coach Gavin MacMillan
Gauff hired MacMillan, a biomechanics specialist, as she looks to solve her serving issues. The two have already started working together, as MacMillan analyzes Gauff’s biggest weakness: her serve. A WTA fan shared Gauff’s picture with a caption that says, “Coco’s new coach is stepping in a lot with advice while she’s serving.”
Coco’s new coach is stepping in a lot with advice while she’s serving pic.twitter.com/NBoH4UhTra
— Owen (@kostekcanu) August 20, 2025
The biggest reason Gauff has not secured the World’s number-one ranking yet is her serve. After her upset fourth-round loss to Emma Navarro at the US Open last year, Gauff parted ways with former coach Brad Gilbert and brought in Daly to improve her serve.
— Tennis Highlights (@TennisHigh61330) September 1, 2024
Daly’s arrival paid immediate dividends, as Gauff won the WTA Tour finals last November. Gauff was expected to soar to the World’s number one ranking this year; however, there have been more lows than highs. Despite the highs, such as Gauff winning her first French Open this year, the lows, such as her upset first-round loss at Wimbledon and her failure to win any of the WTA 1000 hard-court events in America this year, are hard to ignore.
Despite Gauff’s struggles, she remains ranked number three in the World with a nearly 3,000-point lead over fourth-ranked Jessica Pegula. MacMillan notably helped current World number one Aryna Sabalenka take her game to the next level after implementing structural changes to her serve and forehand.
Gauff’s decision to fire Daly occurred after a stretch where she served over 40 double faults at the Canadian Open before losing in straight sets in the fourth round to rising star Victoria Mboko. Gauff also lost in the quarterfinals of the Cincinnati Open to Jasmine Paolini during a match in which she served 16 double faults.
Incredible from Paolini 🤩@JasminePaolini | #CincyTennis pic.twitter.com/IuTaIUkUxI
— wta (@WTA) August 16, 2025
Gauff is generally effective when she gets her first serve, winning nearly 70% of the points this season. However, she’s only won a below-average 43% of second serve points this season. Her 320 double faults also lead the WTA Tour.
Gauff is still one of the favorites in New York, but in hiring MacMillan so close to the US Open starting, she has a clear sense of urgency.
