Rafael Nadal survived his sternest test yet at the Australian Open to safely advance to the quarter-finals at Melbourne Park on Monday.
Wimbledon champion Andy Murray also moved into the last eight, but the Scottish fourth seed enjoyed a considerably smoother path than the world No.1.
Nadal dropped serve - and his nerve - for the first time all campaign before battling past Kei Nishikori 7-6 (7-3) 7-5 7-6 (7-3) in three hours and 17 minutes.
Nadal exchanged angry words with Greek chair umpire Evanthia Asderaki after being hit with a time violation serving at 4-all and deuce in the third set.
The top seed admitted to being rattled after losing the next two points to hand Nishikori the chance to serve out the set.
"I normally have good self control on the court," he said.
"But it is true that the warning was a very critical time.
"I don't want to change no one's rule. We need referees who understand the game. The rules cannot go against the good show. That's all.
"If you are playing with 40 degrees, you cannot expect to have 20 seconds to recover, 25 seconds recover.
"If you are playing crazy rallies, you cannot have 25 seconds to recover because then you will not have more rallies because the players cannot have it.
"So that goes against the fans, against the show."
Nadal was relieved Nishikori, the 16th seed, was unable to capitalise on his rare lapse, with the Spaniard rallying to clinch victory after a second tiebreaker in the tight encounter.
Nadal paid tribute to the vanquished Japanese, saying his speed and deadly backhand had him under pressure throughout.
"He's a fantastic player. He's able to hit the ball very early. That's very difficult.
"I was in trouble. I was close to losing every set.
"The ball was coming back very, very quickly. Today I had to run a lot."
In a rough day at the office, Nadal also needed running repairs for a nasty blister on his racquet hand and a broken shoelace.
"That's never happened before," he said.
Of more concern, Nadal was broken in the fourth game of the match, ending his run of 30 straight service holds, and again in the second set and twice more in the third.
But the 2009 Open champion still found a way to book his spot in a 26th grand slam quarter-final - and seventh from nine starts in Melbourne.
The hard-earned victory - after three routine straight-sets wins - set up a showdown on Wednesday with rising Bulgarian Grigor Dimitrov, the 22-year-old 22nd seed who many rate as a future world No.1.
"He's amazing. He has everything to be the next biggest star," Nadal said. "He has everything to be next in the top positions.
"I hope to play my best match against Grigor. If not, it's going to be impossible."
Dimitrov earlier on Monday defeated Argentinian Roberto Bautista Agut 6-3 3-6 6-2 6-4 to qualify for his first-ever grand slam quarter-final.
Coached by Lleyton Hewitt's former mentor Roger Rasheed, Dimitrov said he was flattered by Nadal's glowing appraisal.
"But (my game) is still a work in progress and the best is yet to come," he said after slamming 11 aces, including one 219kph bullet against his outclassed opponent.
Murray booked his spot in the quarter-finals with a 6-1 6-2 6-7 (8-6) 6-2 victory over Frenchman Stephane Robert, the first lucky loser in history to make the fourth round in Melbourne.