Nadal made to work by Nishikori
Rafael Nadal progressed through to the quarter-finals of the Australian Open with a straight sets victory over Kei Nishikori, but it was a far from comfortable outing for the world number one.
Nadal had won all five of his previous meetings against Nishikori and, while he made it six out of six on Monday, he was pushed hard by his Japanese opponent before sealing a 7-6 (7/3) 7-5 7-6 (7/3) win at Rod Laver Arena.
The 13-time grand slam winner had not been broken previously in the tournament but dropped four of his service games before finally ending the impressive challenge of Nishikori in a match that lasted three hours and 17 minutes.
Next up for the Spaniard is Grigor Dimitrov, who became the first Bulgarian male to reach a grand slam quarter-final after beating Nadal's countryman Roberto Bautista-Agut 6-3 3-6 6-2 6-4.
Nadal looked poised for a straightforward fourth-round outing as he broke Nishikori in the opening game following some loose shots from the world number 17.
The omens were not good for the underdog with Nadal's serve having proved infallible in his opening three matches in Melbourne, but the top seed was finally broken after four uncharacteristic errors in the fourth game.
Suddenly it was the 16th seed who was starting to look the more formidable and Nadal only just managed to hold in his next service game.
The set went with serve to a tie-break, where Nadal showed his superior experience to emerge a 7/3 winner.
Nadal did not have it any easier in the second set either, and he was broken again in the fifth game after putting an overhead smash wide with the whole court to aim for.
That put Nishikori 3-2 in front but Nadal broke back in the eighth, taking the game with a crunching forehand down the line, and the 2009 champion produced a similar shot to take the set as he broke his opponent's serve again in the 12th.
Nishikori continued to fight in the third but his challenge finally looked to be fading as Nadal took a 4-1 lead after breaking in the fourth.
However, Nishikori still posed a major threat to the 2012 runner-up and, after failing to make the most of several opportunities in previous Nadal service games, he broke back in the seventh following the Spaniard's first double-fault of the match.
Incredibly, Nishikori also broke Nadal at his next opportunity to go 5-4 ahead and have the chance to serve for the set.
He could not capitalise though, wasting a great chance for a set point, and Nadal recovered to take that game and he then made no mistake in the tie-break to seal the match.