Briton Emma Raducanu is through to round three at Indian Wells after opponent Dayana Yastremska retired with illness in the opening set.
Raducanu, 21, raced into a 4-0 lead in just 18 minutes during the first set.
Ukrainian Yastremska stepped to the back of the court between games, holding her stomach and then retiring from the contest after being assessed by the medics.
Raducanu will next face world number two Aryna Sabalenka, 25.
Also, American Coco Gauff, 19, had to dig deep to get beyond Clara Burel, winning 2-6 6-3 7-6 (7-4) to secure her place in round three.
After taking the opening set, world number 47 Burel led 2-0 in the second before Gauff found her rhythm to break twice and win 6-3.
Gauff, ranked number three in the world, trailed 4-0 and 5-2 in third and final set, but showed grit when winning six of the following eight games to force a tie-break, which she won on the third match point.
The victory is US Open champion Gauff’s 50th WTA 1,000 win, making her the first teenager to achieve that feat just four days before her 20th birthday.
Japan’s Naomi Osaka is among those to join her in the third round after beating Russia’s Liudmila Samsonova, the 14th seed, 7-5 6-3.
