Indian Wells, United States: American Emma Navarro shocked Australian Open champion Aryna Sabalenka to reach the Indian Wells quarter-finals on Wednesday as Coco Gauff sailed through.
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 6-3, 3-6, 6-2.
US Open champion Gauff, seeded third, celebrated her 20th birthday with a dominant 6-0, 6-2 victory over Belgian Elise Mertens.
It wasn't quite so easy for last year's men's runner-up Daniil Medvedev, but the fourth-seeded Russian managed the windy conditions to post a 6-4, 6-4 triumph over Bulgarian Grigor Dimitrov.
Navarro's victory continues a strong season for the 22-year-old, who won the WTA title in Hobart and reached the semi-finals in Auckland and San Diego.
"It's definitely cool to be able to play an opponent like that and feel like I can hang and I can win," she said. "I've worked really hard over the years to kind of just get to this point and be able to play at a level that can compete with the best players in the world.
"I think that showed today," she added. "She made it really tough on me today, but I was able to play some good tennis in the big moments."
Sabalenka, meanwhile, has found it frustrating 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.
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."
Navarro will face either ninth-ranked Maria Sakkari of Greece or unseeded Diane Parry of France for a place in the semi-finals.
Gauff, who turned 20 on Wednesday, will next face either China's Yuan Yue or 11th-seeded Daria Kasatkina.
"Feels good – finally got a win on my birthday," Gauff said after what she called a "pretty straightforward" victory.
Medvedev said consistency was the key to his victory in windy conditions that made it "very tough" to play from one end of the court compared to the other.
"I think in general I played well. I was really consistent," said Medvedev, who had just 13 unforced errors as he moved a step closer to a first title at Indian Wells – the only hardcourt ATP Masters tournament he has never won.
He will play either 2022 champion Taylor Fritz or seventh-seeded Holger Rune in the quarters.
In other men's matches, American Tommy Paul ended Italian Luca Nardi's dream week with a 6-4, 6-3 victory.
Nardi, who lost in qualifying but gained a place in the main draw as a "lucky loser" thanks to a withdrawal, was coming off a stunning upset of world number one Novak Djokovic in the third round.
Paul will play for a place in the semi-finals against ninth-seeded Casper Ruud, who 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 quarter-final since the series started in 1990.
