MELBOURNE, Australia (AP) -- After the clock ticked past midnight, Andy Murray became aware that it was officially Australia Day and he already knew from the crowd reaction what to expect in the quarterfinals.
Murray, a two-time Grand Slam champion and three-time Australian Open finalist, fended off racket-smashing Grigor Dimitrov 6-4, 6-7 (5), 6-3, 7-5 in a fourth-round match that started Sunday but continued into the early hours of Jan. 26, the national holiday that regularly occurs during the Australian Open.
Midway through his match against No. 10-ranked Dimitrov, who beat him in the Wimbledon quarterfinals last year, Murray heard a distinctive roar that started somewhere in the distance and echoed through Rod Laver Arena.
"I heard a lot of noise -- I had to ask my box what it was for," he said. It was for 19-year-old Nick Kyrgios, who came back from two sets down and saved a match point to beat Andreas Seppi 5-7, 4-6, 6-3, 7-6 (5), 8-6 on Hisense Arena -- the No. 3 court at Melbourne Park -- to become the first Aussie male to reach the last eight at the Australian Open since Lleyton Hewitt in 2005, and the first male teenager since Roger Federer in 2001 to reach two Grand Slam quarterfinals.
Kyrgios has developed quite a reputation for his audacious blend of shots, for his crowd interaction, for his outbursts and for his results: as a wild-entry with a No. 144 ranking at Wimbledon last year, he beat then No. 1-ranked Nadal in the fourth round. That was after he'd saved nine match points and come from two sets down to beat Richard Gasquet in the second round.
As a couple stood to leave Hisense Arena on Sunday during the fifth set -- one in which Kyrgios let a 4-1 lead slip and then had to save break points -- he called out to them: "Hey, where are you going?" The show, evidently, was not over.
His first words after the win, as the crowd continued to chant and scream like soccer fans: "Thanks mate. Feels so good."
"It's crazy," he said. "When I saw I had finally won the match it was incredible -- it was the best feeling I ever had. It's just massive confidence."
Murray, who was broken when serving for the second set and lost the subsequent tiebreaker, rallied from 5-2 down in the fourth set to beat Dimitrov, who shattered his racket on the court after surrendering his last service game.
Murray has a 10-0 winning record against Australian players, but hasn't come across anyone quite as precocious as Kyrgios.
"I would say maybe he's more confident than I would have been at that age ... he obviously backs himself a lot," Murray said. "I'm going to have to play a great match to win against him.
"He's had an unbelievable tournament so far and he's only going to keep getting better. Hopefully my streak doesn't end in a couple of days."
The high-energy night matches overshadowed the day session Sunday, when Nadal continued his comeback from a long-term injury layoff with a 7-5, 6-1, 6-4 win over towering Kevin Anderson to set up a quarterfinal against No. 7 Tomas Berdych, who had a 6-2, 7-6 (3), 6-2 win over Bernard Tomic.
"The chance to be in the quarterfinals after a tough period of time for me is a fantastic result," said Nadal, who didn't let a small thing like his superstitiously and carefully positioned water bottles being knocked over bother him too much. "I was playing better than the days before. The way that I improved my level is not the most important thing; obviously the victory is."
No.2-ranked Maria Sharapova won the last eight games of her 6-3, 6-0 victory over Peng Shuai and will next play seventh-seeded Eugenie Bouchard, who had a see-sawing 6-1, 5-7, 6-2 win over Irina-Camelia Begu. French Open finalist Simona Halep beat Yanina Wickmayer 6-4, 6-2 to set up a quarterfinal against No. 10 Ekaterina Makarova, who beat Julia Goerges in straight sets.
Bouchard made it to the last four at the first three Grand Slam tournaments of 2014, including a semifinal loss on debut at the Australian Open and a semifinal loss to eventual champion Sharapova at the French Open.
"She's playing really well, confident tennis. So aggressive," Sharapova said of the 20-year-old Canadian. "I have a tough match ahead of me, but I always look forward to that."