Naomi Osaka delivered a terrific third set to defeat China's Qinweng Zheng 6-4 3-6 6-1 in the opening round of the Silicon Valley Classic.
Osaka's serve was sharp and it carried her through the match, with 11 aces to Zheng's three, while giving up one break of serve and securing three breaks herself.
After Zheng fought back to win the second set, Osaka was the steady head in the decider, allowing her opponent to implode with three double-faults in crucial points to collect her first win since April.
Osaka will meet Cori Gauff in a star-studded second-round matchup after Gauff dominated Anhelina Kalinina 6-1 6-0.
She was simply too powerful for her Ukrainian opponent, winning 89 per cent (25-of-28) of her first serves to never give Kalinina a chance.
Canada's Bianca Andreescu was eliminated by American Shelby Rogers 6-4 6-2, while Russia's Veronika Kudermetova won a hard-fought battle against Italy's Camila Giorgi 7-6 (7-2) 4-6 7-5.
Meanwhile, in Washington at the Citi Open, Emma Raducanu looked in good touch as she handled the challenge of Louisa Chirico 6-4 6-2 to advance to the second round.
Raducanu will meet Colombia's Camila Osorio after she beat American Sofia Kenin 7-6 (7-2) 6-1, and top-20 talent Victoria Azarenka had no issues against Dayana Yastremska to win 6-4 6-0.
Australian Ajla Tomljanovic continued her strong run of form with a convincing 6-1 6-4 win against American Sloane Stephens, and the Czech Republic's Tereza Martincova recovered from a horrible first set to defeat Xinyu Wang 0-6 6-4 6-4.
Germany's Andrea Petkovic cruised to a 6-2 6-2 win against Denmark's Clara Tauson, and Russia's Anna Kalinskaya defeated American Madison Brengle 6-3 6-0.