NEW YORK :Former champion Coco Gauff launched her U.S. Open campaign with a 6-4 6-7(2) 7-5 win over unseeded Ajla Tomljanovic in the first round on Tuesday, as the American navigated a big test following a late coaching shake-up ahead of the year's final Grand Slam.

Gauff, who arrived in New York after splitting with mentor Matt Daly and hiring biomechanics specialist Gavin MacMillan to address her lingering service issues, made a shaky start under the primetime glare of Arthur Ashe Stadium.

The 2023 champion dropped the opening game on her delivery and produced a flurry of errors but soon shook off the cobwebs and grabbed a 5-4 lead with an ace out wide, eventually taking the first set with a decisive break.

Tomljanovic, who famously battled past Serena Williams in three sets at Flushi

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