Coco Gauff has has 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

Gauff is currently the WTA World No. 3 with a record of 35-12 with one singles title (Roland Garros). She won the 2023 US Open, but failed to defend her title last year. Less than a month later, she fired coach Brad Gilbert.

Coco Gauff, the most popular American tennis player, hadn’t been able to book a practice court. So, she and her newly hired coach, biomechanics expert Gavin MacMillan, braved the mist for close to an hour as they worked on trying to fix her serve.