Carlos Alcaraz was stung on the side of the forehead when a swarm of bees descended on his Indian Wells quarter-final against Alexander Zverev.

Umpire Mohamed Lahyani was forced to suspend play in the third game as the bees invaded the court in California.

The match was delayed for one hour and 40 minutes before defending champion Alcaraz won 6-3 6-1.

"For sure the most unusual match I have ever played in my career," Wimbledon champion Alcaraz said afterwards.

"I saw some bees around, but I thought it was just a few of them. But I saw the sky and there were thousands flying, stuck in my hair, going to me.

"It was crazy. I tried to stay away from them, but it was impossible.

"I'm a little bit afraid of them. I had to stay safe, and I was running everywhere."

The bees were particularly attracted to the spidercam - a TV camera which moves above the court on cables.

Once the players had left the court and spectators had been removed from one corner of the stands, the tournament's beekeeper arrived.

He used a vacuum to suck the bees out of the camera and into a cage so they could later be released - and that appeared to resolve the problem.

However, a few bees continued to trouble world number two Alcaraz on his return, and so the beekeeper was recalled.

He walked on to court to a jubilant reception, to spray the scoreboard before walking back through the crowd where he exchanged high fives and posed for selfies.

"This area, at this time of the year, can be a hotspot for bees, with all the flowers blooming and blossoming," tournament organisers said in a statement.

"In addition, the bees can be attracted to low frequency sound waves, and music bass, as they feel the vibrations and are attracted to those locations."

Alcaraz will play Australian Open champion Jannik Sinner, who is now unbeaten in 19 matches, in Saturday's semi-finals.

"I don't know how I'm going to approach the match," Alcaraz added.

"He's the best tennis player in the world right now, without a doubt. For sure it's going to be the most difficult match that I'm going to play this year."

Sinner earlier extended his winning run to 19 by beating Czech player Jiri Lehecka 6-3 6-3.

World number three Sinner last tasted defeat in last year's ATP Tour Finals - where he lost to Novak Djokovic in the final - and has enjoyed a perfect start to the 2024 season.

His winning streak includes a Grand Slam breakthrough title in Australia in January along with a triumph in Rotterdam last month.

Elsewhere, American 17th seed Tommy Paul held his nerve to beat Norwegian ninth seed Casper Ruud 6-2 1-6 6-3 and reach the last four of the California tournament for the first time.

He will face Australian Open runner-up Daniil Medvedev, who beat Danish seventh seed Holger Rune 7-5 6-4.