Coco Gauff turned her serve from a recurring liability into a decisive weapon and advanced to the US Open second round with a 6-3 6-4 victory over Zeynep Sonmez. The match in New York offered immediate evidence that adjustments made since last season have changed how she starts points.
The opening game set the tone. Gauff produced a 112mph ace and followed with two unreturned first serves to hold inside 90 seconds, establishing pressure from the outset. Across the first set she won 93% of points when her first delivery landed, a rate Sonmez could not counter consistently.
A pivotal sequence in the second set arrived when Gauff saved breakpoint pressure with an ace out wide and an unreturned 115mph serve, a pair of deliveries she said would likely have gone against her a year ago. That moment underlined the blend of speed and placement her team has chased since the change in technique.
Gauff arrived in New York seeded fourth after a week in which she had already claimed the Cincinnati Open title. On the eve of last season’s tournament she brought in biomechanics expert Gavin MacMillan, using work done with Aryna Sabalenka as a template, and altered her serving motion following a damaging run of double faults in Cincinnati. The shift cost comfort at first, but Tuesday’s performance suggested the trade-off is beginning to pay off.
Gauff spoke openly about the difference the work has made. "Now it's like I can look back a year on and think, 'Oh, wow, it's a big difference,'" she said. "It feels good to come into a tournament feeling confident on that shot finally." She also acknowledged the scrutiny last season, adding, "Obviously last year I knew all the eyes were going to be on the serve," and, "Gavin is so great at what he does, I felt a lot of pressure to kind of prove that. It didn't really show within the first two weeks, which is normal."
Statistically the issue has not disappeared. Gauff still leads the tour in total double faults with 301 this season, though her average of 5.6 per match is lower than many peers. Analysts tracking her recent form note she is serving closer to the lines while retaining pace, a mix that powered her Cincinnati title and supported her start in New York.
Gauff will next face either Paula Badosa or Daria Kasatkina in round two, carrying renewed confidence that the serve will function as an aggressive platform rather than a persistent source of anxiety.
