Kyrgios stuns Djokovic

Australian bad boy Nick Kyrgios steamrollered Novak Djokovoc in straight sets at the Mexico Open, dealing a major blow to the world number two's hopes of regaining his mantle of invincibility.

The 21-year-old Kyrgios overpowered Djokovic with 25 aces in the 7-6 (11/9), 7-5 triumph as the Serb sought to rebuild confidence after his shattering second round defeat at the Australian Open in January.

The Australian, letting his tennis skill take centre stage instead of his tantrums, won 81 percent of his first-serve points as he dominated his first ever match with Djokovic.

Djokovic fell in the Australian Open to Uzbekistan's Denis Istomin, then did not play again until this week. He managed only one win, against Slovakia's Martin Klizan, before losing his quarterfinal to Kyrgios.

The world No. 17 Kyrgios delivered another giant killer performance as he also beat Rafael Nadal and Roger Federer in their first ATP tour level meetings.

He is the youngest player to record victories over the tennis Big Five -- Djokovic, Federer, Nadal, Andy Murray and Stan Wawrinka.

Kyrgios will be seeking to reach his first final of the season when he faces big-serving American Sam Querrey in the semis.

Nadal bounced back from a break down in both sets to defeat Japan's Yoshihito Nishioka 7-6 (7/2), 6-3 and book his semifinal spot.

The second-seeded Spaniard, a two-time winner in Acapulco, hammered five aces in the battle between the two lefthanders.

"He is so quick," Nadal said. "I felt I needed to choose the right shots to do the damage. I was trying to hit the winner too early sometimes and too late other times, so it was tough to get my rhythm."