Nadal overcomes Nishikori's challenge to enter quaters

Top seed Rafael Nadal of Spain reached the quarter-finals of the Australian Open after a 7-6 (7-3), 7-5, 7-6 (7-3) win over Japan's 16th-seeded Nishikori Kei here Monday.

Nadal dropped his opening service game. Nishikori succeeded in breaking Nadal four times, and forced the world's No.1 to rally from down in both the second and third sets.

Nadal clinched the second set with two late breaks, but then lost two straight service games in the third set to go from a 3-1 lead to a 4-5 deficit. But the Spaniard stopped Nishikori from serving out the set, prevailed in a tiebreak to claim victory after three hours and 17 minutes.

It is the seventh time for Nadal to reach the quarter-finals in his last seven appearances at Melbourne Park. He missed last year's Australian Open due to a knee injury.

The Spaniard is trying to win his second Australian Open and 14th Grand Slam, so as to equal with Pete Sampras and three behind Roger Federer's leading total of 17. Nadal won his first Australian Open title in 2009, which is the only major he hasn't won at least twice.

Nadal's quarter-finals opponent will be Grigor Dimitrov of Bulgaria. The 22-year-old's breakthrough win came on the same day his girlfriend, Maria Sharapova, lost her fourth-round match to Dominika Cibulkova.