Coco Gauff’s bold decision to overhaul her serve on the cusp of the U.S. Open paid off in a dramatic, if imperfect, win over Ajla Tomljanovic. The 21-year-old American, ranked No. 3 and the 2023 champion, split from coach Matt Daly just days before the tournament and brought in biomechanics specialist Gavin MacMillan—known for fixing Aryna Sabalenka’s serve—to help rectify her season-long serving woes.
In her first match under the new system, Gauff endured a grueling three-set battle, ultimately prevailing 6-4, 6-7 (2), 7-5 over the unseeded Tomljanovic in nearly three hours. Her serving remained inconsistent—she committed 10 double faults and lost six service games—but showed resilience in the final set, where she overcame early miscues to close it out, leaning on her new mechanics and mental trust in the process.
Gauff herself admitted that debuting a revamped service motion in the high-pressure environment of Arthur Ashe Stadium was far from ideal. With only six days of work under MacMillan, she acknowledged that the first round often feels more nerve-racking than a final. Yet, she viewed it as a valuable test under match conditions.
Technical adjustments were on full display throughout the match. Gauff began by serving cautiously—her first-serve average speeds rose incrementally from 88 mph in the opening set to 97 mph in the second, culminating at 101 mph in the decider, even reaching a peak of 117 mph. She described the slower pace as a deliberate choice, designed to preserve the integrity of her new motion under pressure.
Despite the growing pains, Gauff’s resolve and long-term mindset shone through. The move to bring in MacMillan, on top of her longstanding coach Jean-Christophe Faurel, underscores her commitment to a more sustainable, polished serve—viewed as essential to her future success. With a French Open title already this year and a desire to add more Grand Slams, she’s betting that short-term discomfort will fuel long-term gains.
