Acapulco, Guerrero, Mexico, 3 March 2017 | AAP

Nick Kyrgios has delivered a serving masterclass to upset Novak Djokovic and storm into the semifinals of the ATP tournament in Acapulco.

Kyrgios was untouchable on serve, crunching 25 aces in just two sets to send the top seed and 12-time Grand Slam champion crashing out in a 7-6(9) 7-5 quarterfinal boilover.

“It’s a big win,” Kyrgios said.

“I was a little bit nervous because I’m sure the crowd was rooting for Novak. He’s one of the greatest players of all time but I’m playing with confidence.

“My serve is the best part of my game and I had one of my best serving matches tonight.”

In reaching his second ATP semifinal in as many weeks, Kyrgios also joined his Davis Cup captain Lleyton Hewitt as the only player to have conquered Grand Slam giants Roger Federer, Rafael Nadal and Djokovic in their first tour-level match-ups.

While Federer, Nadal and Djokovic were all teenage up-and-comers when Hewitt first beat them, the trio are now bona fide legends of the game, with 44 major singles titles between them and a combined 666 weeks at world No.1.

The world No.17 Kyrgios announced his arrival on the world stage with a thunderous win over Nadal in 2014 on Wimbledon’s grasscourts before beating Federer on clay in Madrid the following year.

Next up for Kyrgios is another big server in unseeded American Sam Querrey, who earlier on Thursday took out fourth-seeded Dominic Thiem 6-1 7-5.

The other semifinal will feature two-time champion and second seed Nadal against third seed Marin Cilic.

Nadal extended his winning streak in Acapulco to 13 matches with a 7-6(2) 6-3 defeat of Yoshihito Nishioka.

Cilic cruised into the last four without picking up a racquet after American Steve Johnson withdrew because of a right ankle injury.