Carlos Alcaraz moved closer to a rare Indian Wells "three-peat" as he breezed past an exhausted Grigor Dimitrov 6-1 6-1 to reach the quarter-finals on Wednesday, while Madison Keys tallied a 15th straight victory by beating Donna Vekic 4-6 7-6(7) 6-3.
Alcaraz, who is bidding to become the third man to win the event three times in a row after Roger Federer and Novak Djokovic, handled the blustery conditions far better than the Bulgarian 14th seed.
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Dimitrov was showing signs of fatigue from his three-hour third-round match earlier in the week and could do little to stop the Spanish world number three, who next faces Argentine Francisco Cerundolo.
"Today with the conditions, it was really tough for us both. I had to survive," he told the ATP Tour.
"I always say in these conditions, you have to survive no matter what. I'm very happy that I was able to play long rallies. I got a good rhythm, even with the conditions, so I'm just really happy to get through."
Alcaraz did not face a break point in the first set as Dimitrov scraped together a handful of winners against more than a dozen unforced errors.
Four-times Grand Slam champion Alcaraz dropped only four of his first-serve points in the second set and snuffed out the three break-point chances Dimitrov had in the fifth game to advance, closing it out with a precision-placed forehand winner.
'GOOSEBUMPS'
Australian Open champion Keys maintained her hot streak with a win over 19th seed Vekic to set up a meeting with the Swiss wildcard Belinda Bencic.
Vekic, the silver medallist in Paris, showed terrific defence in winning the first set, fending off three break points in the second game and another in the fourth.
She had a 5-3 lead in the second set tiebreak but Keys dug in her heels, clinching it with an unreturnable serve as the Croatian thrust her racquet to the court in frustration.
"Sometimes after a close tiebreaker and winning the set and kind of having a little bit of, like, a surge of energy and everything, sometimes you can get almost a little bit too amped," said Keys.
"So I just wanted to try to play really tough the first game and just try to get the thing that I was doing well in order to close out that set."
Keys did exactly that, taking the momentum from the tiebreak and breaking Vekic to open the third. She closed out the comeback win with one of her lethal forehands to wild cheers from the home fans.
Earlier in the day, Bencic pulled off the upset against third seed Coco Gauff 3-6 6-3 6-4.
In a tightly-contested third set, Bencic came back from 0-40 down to break for a 5-4 lead and closed out the victory on her first match point when the American ripped a forward long.
"Obviously, this is why you are practicing and working hard all your life," Bencic said in her on-court interview.
"The way you cheered before the match ... I had chills and goosebumps."
Briton Jack Draper took down another home contender in former champion Taylor Fritz 7-5 6-4 to reach the quarter-finals for the first time, where he will play 11th seed Ben Shelton.
"I played a really high-level match," said US Open semi-finalist Draper. "I think I struggled here in the past with my serve, but I thought that I served great today, and I think that put a lot of pressure on him."
Shelton advanced with a 7-6(6) 6-1 win over fellow American Brandon Nakashima.
Women's top seed Aryna Sabalenka easily dispatched British lucky loser Sonay Kartal 6-1 6-2 and will meet Russian Liudmila Samsonova in the final eight.