(Reuters) -Coco Gauff said her first-round win at the U.S. Open on Tuesday was shaped by a mental battle to trust her revamped serve, as the American third seed worked to overcome old habits during tense moments of her hard-fought victory over Ajla Tomljanovic.
Gauff, the 2023 U.S. Open champion, arrived in New York after splitting with coach Matt Daly and enlisting biomechanics specialist Gavin MacMillan to address lingering issues with her serve.
She made a shaky start under the spotlight of Arthur Ashe Stadium, dropping the opening game on her delivery and producing a flurry of errors before regrouping to clinch a 6-4 6-7(2) 7-5 win over the unseeded Australian.
"The practice week was tough because I was spending a lot of time on court literally serving until, like, my shoulder was hurting," Gauff told reporters.
"I feel like it's in the right direction, and I think for me it's trying not to go back to old habits in those tighter moments, and I think I did that today, especially in the third set ... I think hopefully this time next year I'll be serving much better."
Gauff's serve woes, coupled with inconsistent results after her French Open triumph in June, prompted her coaching shake-up.
Following early exits at Wimbledon and warm-up tournaments in Canada and Cincinnati, the 21-year-old saw her ranking drop from world number two to three.
"Honestly, that third set was the definition of that. That game where I served it at 5-4, that was definitely like an old habit. The next game was a lot better," Gauff said.
"I think the more I get confident, the more I can go for it. Like, I don't think I served so fast today. I would like to get up there in the numbers, but I know I have to get a lot of reps in.
"Ajla played great. I feel like if it was another player, it would be a much more straightforward match ... It's definitely tough going through the match and battling that internal battle. Especially this is the first tournament."
Up next for Gauff is Paris Olympic silver medallist Donna Vekic in the second round.
(Reporting by Pearl Josephine Nazare in Bengaluru; Editing by Himani Sarkar)
