American Emma Navarro stunned world No. 2 Aryna Sabalenka 6-3, 3-6, 6-2 to record the biggest win of her career and reach the Indian Wells quarterfinals for the first time on Wednesday while Coco Gauff celebrated her birthday by advancing with ease.
Navarro absorbed Sabalenka's powerful serve and converted four of her five break-point opportunities to beat the reigning two-time Australian Open champion in windy conditions.
Navarro came out flying to grab the first set before Sabalenka raised her level in the second to force a decider.
The even-keeled Navarro kept her cool, fending off a break point and smacking a forehand winner for a crucial service hold and a 4-1 lead.
Navarro, seeded 23rd, broke the hard-hitting Belarusian for a fourth time on match point to book a quarterfinal clash with ninth seed Maria Sakkari of Greece.
Sakkari, the 2022 runner-up, beat Frenchwoman Diane Parry 6-2, 3-6, 6-3.
Navarro, who is known for keeping her emotions under wraps, did a subdued fist pump after winning the match in front of a supportive crowd at Stadium One.
"It's a little bit unnatural for me to be in the spotlight and be playing on a court like that with a ton of fans and TVs and eyes on me. It's not my natural way," she told reporters.
"But I feel I'm definitely getting more comfortable with it and just feeling like I can be myself even if there's however many people watching.
"Also I think that was my second or third fist pump ever. If it was a little weird, cut me some slack," she said with a smile.
With the win Navarro will break into the top 20 for the first time after the tournament and Sabalenka, who won her second Grand Slam crown in Melbourne Park in January, praised her opponent.
"Her potential is really great," Sabalenka told reporters.
"I think she has the potential to be in the top 10."
Gauff dominated Elise Mertens to win 6-0, 6-2 on her 20th birthday and book her spot in the quarterfinals.
The dynamic American played her best tennis of the tournament so far, serving well and stepping into the court to overwhelm the Belgian 24th seed.
Mertens was unable to back up her win over Naomi Osaka in the previous round, hitting just four winners to 21 unforced errors in a match that lasted just over an hour.
Third seed Gauff saw her section of the draw open up after Sabalenka's defeat and will play unseeded Yuan Yue of China, who fought back from a set and a break down to beat Russian 11th seed Daria Kasatkina 4-6, 6-4, 6-3.
Yuan, who claimed her first WTA title in Texas this month, stunned compatriot and Australian Open runner-up Zheng Qinwen in the second round and will look for another upset to extend her nine-match winning run.
