Gauff has not appeared confident with her serve since beating Aryna Sabalenka on clay earlier this summer. She won three matches in the US Open tuneup earlier at the Cincinnati Open, but lost to Italy's Jasmine Paolini in the fourth round.

Tennis star Coco Gauff hired biomechanics expert Gavin MacMillan, who previously helped world number one Aryna Sabalenka improve her serve.

Gauff hired Daly, a grip specialist, to work on her serve and forehand after she fired then-coach Brad Gilbert following a disappointing fourth-round exit at the 2024 US Open on the heels of her victory at the tournament in 2023. Daly worked with Gauff as she won the French Open this summer, claiming her second career Grand Slam tournament victory.

Festivities surrounding the 2025 US Open have already begun, but WTA World No. 3 Coco Gauff is making major last-minute adjustments to her team before the final Grand Slam of the season. Gauff has parted ways with coach Matt Daly and J.C. (Jean-Christophe) Faurel, bringing in biomechanics expert Gavin MacMillan, per multiple outlets.

Coco Gauff has stunned the tennis community by making a major career move ahead of the 2025 US Open. The American decided to part ways with her coach Matt Daly just days before her campaign at the New York Major.