Carlos Alcaraz battled through a bee swarm delay to clinch a remarkable 6-3, 6-1 victory over Alexander Zverev, securing his spot in the BNP Paribas Open semifinals on Thursday night.

During the match, Alcaraz had to fend off bees buzzing around him before taking cover, leading to a 19-minute suspension with the score tied at 1-1 in the first set.

The unexpected interruption was caused by dozens of bees attaching themselves to the overhead spider camera, which required a man to use a vacuum to clear them off.

A spray bottle was used to ensure the safety of the players and spectators, as the bees also landed on seats and walls around the court.

After a delay of one hour and 48 minutes, the match resumed, with the actual playing time amounting to 1 hour and 29 minutes.

In another thrilling match, Jannik Sinner defeated Jiri Lehecka 6-3, 6-3, extending his winning streak to an impressive 16 consecutive matches this year. Sinner's outstanding performance includes winning the Australian Open title in January and maintaining a perfect 19-0 record since last year's Davis Cup. He has also won 21 of his last 22 sets.

Sinner's remarkable form sets up an exciting semifinal clash with Alcaraz on Saturday.

"You earn these things by working hard and believing," Sinner said in a Tennis Channel interview. "I'm just glad to be in this equation. It doesn't matter if you're 16-0 or whatever."

Sinner made just four unforced errors in the first set when Lehecka had 17 miscues.

Sinner got the lone break in the second set in the fourth game with a backhand winner. Lehecka erased Sinner's first match point in the eighth game before Sinner converted his fourth match point in serving it out.

"I've improved many things, which makes me more confident in the court," Sinner said.

Tommy Paul rallied past ninth-seeded Casper Ruud 6-2, 1-6, 6-3 to reach his second career Masters 1000 semifinal. The American won 25 points at the net, which was part of his game plan.

"It was to play aggressively, come out and play my game and make him uncomfortable, especially on the pressure points," Paul said. I broke the (racket) string on match point and was like, 'Oh no,' and kind of rushed the net and hoped for the best."

Paul will play fourth-seeded Daniil Medvedev in the other semifinal. Medvedev defeated Holger Rune 7-5, 6-4 on Thursday.

Top-ranked Iga Swiatek rallied from a 1-4 deficit in the first set and advanced when Caroline Wozniacki had to quit their quarterfinal.

Coco Gauff defeated Yuan Yue 6-4, 6-3 in 1 1/2 hours despite 17 double faults against seven aces.

Marta Kostyuk of Ukraine defeated Russian Anastasia Potapova 6-0, 7-5 for the first time in three career meetings to reach the semifinals.

Maria Sakkari outlasted Emma Navarro, 5-7, 6-2, 6-4, for the final slot in the semis.

Swiatek was leading 6-4 and had just broken Wozniacki to open the second set when the Dane retired because of a right foot issue. She had jammed a toenail on her foot earlier in the tournament and had a trainer retape it between sets.

Wozniacki, the 2011 tournament champion and former world No. 1, raced to a 4-1 lead in the first when Swiatek committed many of her 17 unforced errors.

But Swiatek turned it on from there, winning the final five games to take the first set. She broke Wozniacki in a four-deuce game to close out the set in which Swiatek had 17 winners in front of actor Will Ferrell.

Swiatek moved on to the semifinals for the third straight year in the Southern California desert, having dropped just 14 games in her matches so far. Wozniacki was in the seventh tournament of her comeback since retiring 3 1/2 years ago, marrying and having two children.

All eight quarterfinals were being played on the same day for the first time at the combined ATP Tour and WTA Tour event.