Nick Kyrgios, a 19-year-old wild card from Australia with a world ranking of 144, served 37 aces and used a fearless go-for-broke style -- he even hit a winning between-the-legs shot -- to beat the No. 1-ranked Nadal 7-6 (5), 5-7, 7-6 (5), 6-3 and reach the quarterfinals on Tuesday.
"I was in a bit of a zone out there," Kyrgios said. "I played some extraordinary tennis."
Playing in his first Wimbledon and fifth major, Kyrgios is the first player outside the top 100 to defeat a No. 1 at a Grand Slam since No. 193 Andrei Olhovskiy downed Jim Courier in the third round at Wimbledon in 1992.
Kyrgios served out the match against two-time champion Nadal at love, hitting an ace on match point. He dropped his racket to the Centre Court turf and held his head in his hands in amazement. He did a little dance to celebrate.
"That's the biggest win of my career obviously, and that's something I'm never going to forget," he said. "I'm going to draw so much confidence out of that no matter where I play now."
Kyrgios is the first man to get to the quarterfinals in his Wimbledon debut in 10 years, the first teenager to defeat a No. 1 at a Grand Slam since a 19-year-old Nadal beat Federer at the 2005 French Open, and the lowest-ranked player to defeat Nadal at any Slam.
For Nadal, a two-time Wimbledon champion and 14-time major winner, it marked another shocking loss at the All England Club. In 2012, he was ousted in the second round by 100th-ranked Lukas Rosol. Last year, he fell to No. 135 Steve Darcis.
"The thing is this surface, when you have an opponent who decides to serve and to hit every ball very strong, you are in trouble," Nadal said. "In the second and the third set I was better than him, but I was not able to convert opportunities. And for the rest, he played better than me."
Kyrgios, who saved nine match points in a second-round win over Richard Gasquet, looked like a star in the making, showing no nerves, flashing winners from all over the court, and dictating the play.
The 6-foot-4 (1.93-meter) Australian struck 70 winners, compared to 44 for Nadal. He dominated with his serve, with a fastest delivery of 133 mph (215 kph). He hit a casual winner between his legs from the baseline in the second set.
Kyrgios will next face eighth-seeded Milos Raonic, the first Canadian man to reach the Wimbledon quarterfinals since Robert Powell in 1912. He beat No. 10 Kei Nishikori of Japan 4-6, 6-1, 7-6 (4) 6-3.
Roger Federer kept up his bid for a record eighth Wimbledon title, beating Tommy Robredo 6-1, 6-1, 6-4 to reach the quarterfinals without the loss of a set.
The fourth-seeded Federer, who has not dropped a set in the entire tournament, overwhelmed the Spaniard 6-1, 6-1, 6-4 in just over 90 minutes on No. 1 Court. He hit 11 aces, faced only one break point -- in the final game of the match -- and broke four times in a performance that showed he remains a real contender at the age of 32.
"It's really nice the way I'm playing," Federer said. "I'm serving well, moving well, returning all right, so all the things are happening that need to be happening to go deep in this tournament again."
Federer received a standing ovation after closing out the match with a serve-and-volley point, hitting a backhand volley that Robredo couldn't handle.
The win avenged Federer's straight-set loss to Robredo in their last meeting in the fourth round of the U.S. Open. Apart from that defeat, Federer has won all of his 11 matches against the Spaniard.
Federer has lost only 32 games in four matches at the All England Club, the same number as defending champion Andy Murray.
"Clearly I'm very pleased with the first week, and here we go now into the quarters," Federer said. "It's always really exciting being so deep into a tournament and feeling you are closer to the finish line.
"I've played a lot of matches so things are exactly where I want them to be, but then again you're sort of only in the quarterfinals and that's when the tournament kind of really starts."
Federer's win set up an all-Swiss duel with Australian Open champion Stan Wawrinka, who beat Feliciano Lopez 7-6 (5), 7-6 (7), 6-3 to make it to the Wimbledon quarterfinals for the first time.
Federer holds a 13-2 record against Wawrinka, though Wawrinka won their last encounter in the Monte Carlo final in April.
Eighth-seeded Milos Raonic became the first Canadian man to reach the Wimbledon quarterfinals since Robert Powell in 1912, beating No. 10 Kei Nishikori of Japan 4-6, 6-1, 7-6 (4) 6-3.
The Associated Press contributed to this report.
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