Carlos Alcaraz said he surprised himself by staying focused despite being stung on the forehead at Indian Wells on Thursday after the Spaniard’s quarter final match against Alexander Zverev was interrupted by a swarm of bees.

The world No.2 was serving in the third game of the match when the bees descended upon him. The 20-year-old tried swatting them away with his racket but eventually ran for cover after being stung.

Alcaraz, who emerged with a 6-3, 6-1 victory to keep his title defence on track, said the bees were all over him. “I saw some bees around but I thought it was just a few of them, just not too many,” he told reporters.

“But I saw the sky and there was thousands flying, stuck in my hair, going to me. It was crazy. I tried to stay away from them, but it was impossible.”

Play resumed after an hour and 48 minutes, during which a beekeeper was called to control the situation.

“I couldn’t stay focused on the ball, I was focused on the bees and tried to (keep them) away. That’s why we stopped a few more times before the match began again. After that, we decided to warm up and I saw that the bees weren’t around anymore. I tried not think about them anymore.

“It was a really important game for me. I surprised myself that I stayed focus on the match, not on the bees.”

Italian Sinner continued his perfect start to the season by cruising past Jiri Lehecka 6-3, 6-3 to improve his win-loss record this year to 16-0.

Local hope Tommy Paul also reached the semi-finals with a 6-2, 1-6, 6-3 win over Casper Ruud. He will play fourth seed Daniil Medvedev who defeated Holger Rune 7-5, 6-4.

American Coco Gauff, who beat China’s Yue Yuan 6-4, 6-3 in a quarter final later, said she was relieved to avoid the invasion.

“That’s the craziest thing I’ve ever seen happen at a tennis court,” Gauff said. “Hopefully it will never happen again, at least not to me.”

Marta Kostyuk of Ukraine defeated Russian Anastasia Potapova 6-0, 7-5. Maria Sakkari outlasted Emma Navarro 5-7, 6-2, 6-4 for the final slot in the semis.

Top-seed Iga Swiatek got a walkover when Caroline Wozniacki had to quit their quarter final. Swiatek was leading 6-4 and had just broken Wozniacki to open the second set when the Dane retired with a foot issue.