Japan's Naomi Osaka, back from a 2 1/2-month absence, fought for a first-round win in the Mubadala Silicon Valley Classic on Tuesday, beating China's Qinwen Zheng 6-4, 3-6, 6-1.
Osaka hadn't played since losing in the first round of the French Open. She sat out the subsequent grass-court season, including Wimbledon, because of an Achilles injury.
Osaka, the 2018 and 2020 U.S. Open champion, put less than half of her first serves in play against Zheng but came through when it mattered, saving 7 of 8 break points. Osaka had an 11-3 edge in aces, and Zheng amassed more double faults, 7-2.
In other first-round action, ninth-seeded Veronika Kudermetova of Russia eked out a 7-6 (2), 4-6, 7-5 win over Italy's Camila Giorgi. The United States' Shelby Rogers downed Canada's Bianca Andreescu 6-4, 6-2, and Caroline Dolehide won an all-U.S. matchup against Kayla Day 7-6 (5), 6-4.
Sixth-seeded Coco Gauff cruised past Ukraine's Anhelina Kalinina 6-1, 6-0.
Second-seeded Emma Raducanu of Great Britain opened her summer hard-court season with a 6-4, 6-2 over the United States' Louisa Chirico in Washington.
Raducanu, 19, last played at Wimbledon, where she lost in the second round to France's Caroline Garcia.
Chirico, ranked 216th in the world, didn't help her cause by committing eight double faults while firing just one ace. Raducanu, the reigning U.S. Open champion, had three aces and no double faults.
Other first-round winners included fourth-seeded Victoria Azarenka of Belarus, Russia's Anna Kalinskaya, Australia's Ajla Tomljanovic, the Czech Republic's Tereza Martincova, China's Xiyu Wang and Colombia's Camila Osorio. Germany's Andrea Petkovic upset eighth-seeded Clara Tauson of Denmark 6-2, 6-2.
--Field Level Media