Serena Williams defeated former world number one Victoria Azarenka 7-5 6-3 to reach the third round at Indian Wells.
Williams, in her first tournament since a quarter-final exit at the Australian Open, needed more than two hours to get past her long-time rival.
“It’s hard to play somebody you’re so close to,” Williams said. “It’s also invigorating.”
Britain’s Johnanna Konta beat Taiwan’s Hsieh Su-Wei 6-0 6-2 but Dan Evans lost 6-7 (4-7) 6-3 6-3 to Stan Wawrinka.
World number 45 Konta won the first eight games and saved three break points when serving at 3-2 in the second.
Her 33-year-old opponent, ranked 27, spurned 12 break-point opportunities in total.
World number four Sloane Stephens made 32 unforced errors as she lost 6-3 6-0 to Swiss qualifier Stefanie Vogele.
Vogele needed just over an hour to dispatch the fourth-seeded Stephens and push her overall record to 4-1 against the 2017 U.S. Open champion.
Williams, winner of 23 Grand Slam singles titles, will play Garbine Muguruza in the third round after the 20th-seeded Spaniard beat American Lauren Davis 6-1 6-3.