MELBOURNE, Australia -- Top-ranked Rafael Nadal has advanced to the quarterfinals of the Australian Open after a 7-6 (3), 7-5, 7-6 (3) win over Kei Nishikori of Japan.
He was broken twice in the third set -- getting a time violation from chair umpire Evanthia Asderaki in one of them.
Nadal is trying to win the Australian Open for the second time -- his first title came in 2009 -- and secure the 14th major of his career, equal with Pete Sampras and three behind Roger Federer's leading total of 17. The Australian Open is the only major he hasn't won at least twice.
It's the seventh time in Nadal's last seven appearances at Melbourne Park that he's advanced to the quarterfinals. He didn't play the Australian Open last year due to a left knee injury and stomach virus.
Nadal will play 22-year-old Bulgarian Grigor Dimitrov on Wednesday. Dimitrov advanced to his first Grand Slam quarterfinal in his 14th attempt after beating No. 11 Roberto Bautista Agut 6-3, 3-6, 6-2, 6-4 on Monday. He clinched the match by breaking Bautista Agut's serve for the fourth time.
The 22-year-old Bulgarian's breakthrough win came on the same day his girlfriend, Maria Sharapova, lost her fourth-round match to Dominika Cibulkova.
Until recently, the 22-year-old Bulgarian has been known as "Baby Fed" because of the one-handed backhand he has in common with Roger Federer, and is also widely known as Sharapova's boyfriend. He's making his own way in Melbourne.
Wimbledon champion Andy Murray ended lucky loser Stephane Robert's unexpected run at the Australian Open with a 6-1, 6-2, 6-7 (6), 6-2 win over the Frenchman in a fourth-round match Monday. Murray wasted two match points on serve in the 10th game of the third set and two more in the tiebreaker before Robert rallied to send it to a fourth.
The three-time Australian Open finalist has faced only one player ranked inside the top 100 -- No. 26 Feliciano Lopez, who he beat in the third round -- in three of his four matches this tournament. Murray will play the winner of Monday's later match between 2008 finalist Jo-Wilfried Tsonga and four-time Australian winner Federer.