Cameron Norrie's Indian Wells title defence was ended by the rising 18-year-old Carlos Alcaraz, who will face Rafael Nadal - unbeaten in 2022 - next.

Spaniard Alcaraz reached the quarter-finals at last year's US Open.

Nadal won his 19th consecutive match since the start of the year with a 7-6 5-7 6-4 win over Nick Kyrgios.

Australian Kyrgios was broken when serving for the first set, and was warned after smashing his racquet in frustration.

He conceded the tiebreak 7-0 on a penalty point after being penalised for an audible obscenity directed at a heckler in the crowd.

The Australian world number 132 was unhappy with the noise the crowd made throughout the match and when he lost the deciding set he again smashed his racquet into the court.

It bounced and shot forward, narrowly missing a ball boy who had to take evasive action at the back of the court.

"Did I throw the racquet anywhere near him originally?" Kyrgios replied when quizzed about it after the match.

"It landed a metre from my foot and skidded and nearly hit him. I'm human. Things happen like that.

"Obviously it was a very misfortunate bounce. I think if I did that a million times over it wouldn't have gone that way.

"That's a question you're going to say after a three-hour battle against Nadal? He ducked. It was a complete accident. I didn't hit him, thankfully. It wasn't my intention."

Kyrgios later tracked the ball boy down to apologise and promised to bring a racquet to the venue for him later on Friday.

Kyrgios also felt umpire Carlos Bernardes allowed the crowd to be too noisy during points.

"I know when you play Rafa, like, 99% of the crowd is going to go for these guys," he continued.

"I just want people to know that you're a spectator. You've bought tickets to come watch us play. At least don't scream out before first and second serve.

"I think it's just this generation. Everyone feels like their opinion is valid. It is getting worse because of social media, people think that they're relevant all of a sudden.

"You're not relevant. You have a little social media account that you type to people on. You spread negativity. It's embarrassing, and you can see how it affects people."

Alcaraz 'humble enough to work hard' - Nadal

Norrie was twice a break up in the first set against Alcaraz but was unable to capitalise.

He also broke first in the second set, but was broken back after some treatment for tightness in his left hip, and Alcaraz - with exhilarating power and pace - completed a straight sets victory.

"I didn't feel that much different at all, as defending champion," Norrie said.

"It's always nice to back that up, and know that it wasn't just a one-off event. I won [recent ATP tournaments in] Delray Beach and then Acapulco, and I felt like I was playing at the level that I was last year."

Nadal is chasing a fourth BNP Paribas Open title, but accepts he will have his work cut out against Alcaraz, who is nearly half his age.

"I think he's unstoppable in terms of his career," he said.

"He has all the ingredients. He has the passion. He's humble enough to work hard. He reminds me a lot of things I did when I was a 17- or 18-year-old kid.

"I think he has the passion. He has the talent and the physical component that is great. And I am super happy, even if, of course he's going to be a great rival."

Another Spaniard, Paula Badosa, is still on course to defend the women's title.

The fifth seed beat the 21st seed Veronika Kudermetova 6-3 6-2 and will play Maria Sakkari of Greece in Friday's semi-finals.

The sixth seed, who reached the semi-finals of both the French Open and US Open last year, was a 7-5 6-4 winner over Elena Rybakina of Kazakhstan.