The fourth-seeded American, who won her maiden Grand Slam title in New York three years ago, looked assured as she negotiated the rain-delayed conditions to move safely into the second round.
Gauff arrived at Flushing Meadows with confidence boosted by her first title of the season in Cincinnati and growing belief that the serve which has frequently determined the quality of her performances is becoming a more dependable part of her game.
At 22, Gauff is now chasing a third major championship, while also having a mathematical route to the top position in the WTA rankings.
She made a fast start against the 54th-ranked Sonmez, opening with a love hold that featured two early aces. The Turkish player, however, refused to be overwhelmed and matched Gauff in the powerful baseline exchanges during the opening five games.
Gauff eventually found the breakthrough in the sixth game, breaking Sonmez without conceding a point. She then negotiated a difficult service game to move 5-2 ahead before Sonmez briefly extended the set.
The American made no mistake when serving for the opening set, closing it out after 33 minutes.
The heavy rain outside created an unusual atmosphere inside Arthur Ashe Stadium, with the sound of the downpour reverberating against the closed roof throughout the contest.
Sonmez Fights Back
The second set presented Gauff with a tougher challenge.
She broke in the opening game and appeared ready to take control, but Sonmez responded aggressively, moving forward more frequently and capitalising on a brief dip in Gauff’s level.
The Turkish player broke back to level the set at 2-2 after producing a powerful backhand winner.
Gauff was then forced to withstand her most difficult passage of the match during a marathon service game at 2-3. She saved three break points before finally escaping, sealing the hold with a 115mph ace down the middle.
“I knew if I could hold that game, I felt confident breaking the next game,” Gauff said.
Her prediction quickly became reality.
Sonmez surrendered the decisive break after committing two double faults, allowing Gauff to move ahead once again. The American consolidated the advantage to lead 5-3 before serving out the match to love.
Gauff completed the victory in one hour and 20 minutes.
Serve Becoming a Strength
Beyond the result, the performance offered another indication that Gauff’s work on her serve is beginning to produce tangible results.
The American has long been regarded as one of the strongest defensive players on the women’s tour, but her serve has often been the determining factor in her performances. When it falters, pressure can quickly spread to the rest of her game.
Conversely, an effective first serve has increasingly allowed her to dictate points and play more aggressively.
That was particularly important during her 2025 US Open campaign, when she arrived in New York amid a significant technical overhaul of her serve. Her struggles eventually contributed to a fourth-round defeat by Naomi Osaka.
This year, however, there have been more encouraging signs. Gauff reached the semi-finals at Wimbledon and in Canada before going on to win the Cincinnati title, providing evidence that the changes to her service motion are beginning to pay off.
Following Tuesday’s victory, she explained that the improvement has come gradually, particularly through adjustments to her ball toss and wrist position.
“I don’t even realize how much it looks different until someone posted a video of me serving even in Miami Open this year,” she said. “My serve looks different now.”
Against Sonmez, Gauff landed 62 per cent of her first serves, reached a top speed of 125mph and produced five aces against three double faults.
She won 71 per cent of points behind her first serve and, perhaps more significantly, claimed nearly two-thirds of the points when forced to rely on her second delivery.
The consistency meant she was broken only once during the match and gave herself greater freedom to attack from the baseline.
‘It Does Take a Lot to Break Me’
Gauff also believes the improvement in her serve has been accompanied by a change in her mental approach.
“It does take a lot to break me,” she said, reflecting the growing resilience that has become a defining feature of her game.
The victory sets up a second-round meeting with either Daria Kasatkina or Paula Badosa. Their opening-round match was suspended because of rain, with Badosa leading 6-1, 5-4 when play was halted.
But Gauff’s ambitions in New York extend beyond simply progressing through the draw.
She is one of four players still capable of finishing the tournament as the WTA’s world No. 1, alongside current No. 1 Aryna Sabalenka, Elena Rybakina and Jessica Pegula.
For Gauff to rise to the summit, she must win the US Open while Rybakina must exit before the semi-finals.
A Different Mindset in New York
The additional pressure of competing in front of a home crowd has traditionally made the US Open a particularly demanding tournament for Gauff.
This time, however, she has spoken about trying to approach the event differently by focusing less on the final result and more on enjoying the experience.
That shift was evident before Tuesday’s match.
Gauff admitted she felt nervous while waiting in the tunnel before walking onto Arthur Ashe Stadium, but said those nerves disappeared once she began warming up.
“I don’t know, it was just a weird feeling today that I felt pretty calm,” she said. “I don’t know what put my mind at ease. I think just maybe the confidence I had this week and knowing, like, the opponent would have to play a really high level and me a really low level maybe for it to not go my way.”
Three years after becoming a US Open champion at 18, Gauff has returned to New York with a different combination of experience, confidence and expectation.
Her opening victory suggests she is ready for the challenge.