American Emma Navarro shocked second-seeded Australian Open champion Aryna Sabalenka 6-3, 3-6, 6-2 on Wednesday to reach the quarterfinals of the WTA and ATP Indian Wells Masters.
Navarro, ranked 23rd in the world, pushed Sabalenka hard on a breezy Stadium Court to notch her first career win over a top-five player.
"Feeling really good," Navarro said after wrapping up the win in just under two hours. "It's never easy coming out and playing an opponent like that – so experienced and just so talented, obviously.
"She made it really tough on me today, but I was able to play some good tennis in the big moments."
The victory continues a strong season for 22-year-old Navarro, the 2021 US collegiate champion who won the WTA title in Hobart and reached the semifinals in Auckland and San Diego.
Sabalenka, meanwhile, has found it frustrating going since her successful title defense at the year's first Grand Slam. The Belarusian's fourth-round exit follows her opening-match defeat in Dubai last month.
Navarro will face either ninth-ranked Maria Sakkari of Greece or unseeded Diane Parry of France for a place in the semifinals.
After the two exchanged just two breaks of serve in the first two sets, Navarro came out ahead as they traded three straight breaks in the third to take a 3-1 lead.
She broke Sabalenka again to seal the match, finishing with 22 winners to 14 unforced errors while Sabalenka's 38 winners were countered by 34 unforced errors.
Sabalenka, who saved four match points to win her opener against 64th-ranked American Peyton Stearns, acknowledged that she never really got comfortable in the California desert this year.
"I tried to adjust. We tried to work on couple of things, make sure I'm there and I'm fighting for this title," she said. "I would say that we did our best and we'll learn. We'll work a little bit more on the movement, and hopefully I'll be ready for Miami."
She didn't blame a lack of matches since Melbourne, saying a player of her experience should be able to summon her best game regardless.
But Navarro was able to keep her from finding a rhythm.
"Forehand, really great forehand," Sabalenka said of Navarro's strengths. "Overall I would say she's moving well and playing some different rhythms so you always have to adjust.
"If your movement is not there, then you will always be off the rhythm and you'll be missing a lot of shots and making a lot of unforced errors.
"That's what actually happened to me. I wasn't moving that great today, and that's why she forced me for all those unforced errors."
RUUD REACHES QUARTER-FINALS
In other early matches, men's ninth seed Casper Ruud rallied to beat French veteran Gael Monfils 3-6, 7-6 (7/3), 6-4.
Norway's Ruud stepped up his attack in the second two sets, finishing by winning 16 of 20 points at the net and earning his only break of the match early in the third to foil Monfils' bid to become the second-oldest player, after Roger Federer, to reach an ATP Masters 1000 quarterfinal since the series started in 1990.
In the quarterfinals Ruud will face either American Tommy Paul or Italy's Luca Nardi – the lucky loser who toppled world No 1 Novak Djokovic in the third round.
Fourth-ranked Daniil Medvedev, runner-up to Carlos Alcaraz last year, faced Bulgarian Grigor Dimitrov for a place in the quarterfinals while 2022 Indian Wells champion Taylor Fritz took on seventh seeded- Holger Rune of Denmark.