INDIAN WELLS, Calif. -- Coco Gauff gave herself an early birthday present by beating Lucia Bronzetti 6-2, 7-6 (5) on Monday in the third round of the BNP Paribas Open.

Gauff, who turns 20 on Wednesday, struggled early but found a way to hold her serve by saving 10 of 11 break points. She closed out the match with a serve into the body that Bronzetti couldn't return. It extended Gauff's winning streak in the United States to 18 matches, a run that includes winning the title at last year's U.S. Open.

Bronzetti had a chance to force a third set when she took a 5-4 lead in the tiebreaker. Gauff won the next three points.

These days, Gauff is finding ways to win when she doesn't necessarily have all her shots tuned in.

"The mentality is the reason why I'm playing and the reason why I'm being successful," said Gauff, who will play a doubles match with partner Jessica Pegula later in the evening. "I'm not always playing my best, but mentally when I show that each match I'm not going to give up, it gives something for the opponent to think about."

Gauff will face Elise Mertens in the round of 16. Mertens held off Naomi Osaka 7-5, 6-4. Osaka played in the fifth tournament of her return after her maternity leave in 2023.

"Elise, she's always a tough opponent to play. It's never an easy match against her," Gauff said. "She doesn't give you much leverage. For me, just going to have to approach being aggressive. Also, just trusting my strokes and trusting myself."

Two-time Australian Open champion Aryna Sabalenka beat Emma Raducanu 6-3, 7-5 to advance. Sabalenka, the No. 2 seed, stayed composed in times of stress. She's been known to smash a racket - something she's trying to change.

"It's a new approach to tough situations," Sabalenka said on the television broadcast. "Don't focus on the negative and try to stay positive."

On the men's side, 20-year-old Luca Nardi from Italy used a combination of poise and power to stun his boyhood idol and top-seeded Novak Djokovic with a 6-4, 3-6, 6-3 win.

"This is a miracle," Nardi said in an interview after the match on the Tennis Channel. "I'm a 20-years-old guy, 100 in the world, and beating Novak. So, crazy. Crazy."

No. 7 Holger Rune played his first match of the tournament and beat Lorenzo Musetti 6-2, 7-6 (5) to advance to the round of 16. Rune had a bye in the first round and advanced through the second when Milos Raonic withdrew with an injury.

"I was very eager to play," Rune said.

He will face No. 12 Taylor Fritz, the 2022 champion.

Gael Monfils produced a stunning display of shot-making and showmanship to rally from a set and 3-0 down to beat Cameron Norrie, the tournament's 2021 winner, 6-7 (5), 7-6 (5), 6-3 in a match that took more than three hours.

The 37-year-old Frenchman electrified the crowd with his creativity to set up fourth-round meeting with ninth seed Casper Ruud.

Norrie, who won the tournament in 2021, piled up 60 unforced errors and could not solve the unpredictable Monfils puzzle in the 3-hour and 15-minute affair.

Americans Taylor Fritz and Tommy Paul won in straight sets.

In the nightcap, No. 4 Daniil Medvedev's was just good enough, as he edged No. 29 Sebastian Korda 6-4, 5-7, 6-3 and will face No. 13 Grigor Dimitrov next.

The Associated Press and Reuters contributed to this report.