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 face Peyton Stearns or Aryna Sabalenka in round three.
Asked about Yastremska’s illness, Raducanu said: “I had zero idea to be honest. It surprised me, I was just trying to focus on my side of the court as much as possible and I did that well from the start.
“I played pretty clean for four games and I just feel bad for Dayana because she’s been through a lot and I just hate seeing people injured. I really empathise with her. I’ve been through both injury and illness and it completely sucks – it’s the worst thing that can happen to you as an athlete.”
Wild card Raducanu broke Yastremska’s serve in the opening game with a well-placed drop shot and then dug in to save a break point during her first service game.
A strong backhand sealed a second break before Raducanu comfortably held in the fourth game.
Yastremska also retired with an injury during her only other meeting with Raducanu at Portoroz in Slovenia in 2022.
It is the first time Raducanu has registered successive victories since she won three in a row to reach the fourth round at Indian Wells in March 2023.
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.
“I’m happy with the mental fight,” Gauff told Sky Sports.
“It wasn’t my best tennis. It’s not about how you show up on your good days, it’s about how you show up on bad ones – and I’m happy with how I showed up today.”
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.
