Novak Djokovic described it as a day to forget after the Serb made 100 unforced errors in his battling five-set win over Gilles Simon at the Australian Open.
Djokovic was far from his metronomic best at Rod Laver Arena as he missed 51 forehands, 48 backhands and was broken four times.
Simon, however, was unable to capitalise as the world number one dug deep to grind out a 6-3 6-7 (1/7) 6-4 4-6 6-3 victory and book a quarter-final match-up with Japan's Kei Nishikori.
"I was obviously pleased to win the match. The last point counts. But in terms of the performance itself, I haven't done well at all," Djokovic said.
"I honestly didn't expect to make this many unforced errors. In terms of a level that I've played, it's the match to forget for me."
Andy Murray has made almost half as many unforced errors (63) in his opening three matches put together as Djokovic managed against the Frenchman.
Asked if he could remember a similar performance, Djokovic said: "Not even close. No, I don't think I've had any close number to a hundred.
"But, again, there is a first time for everything."
He added: "It gives me great joy to know that I can't get worse than what I played today. It doesn't concern me for the next one."
Nishikori will offer a similar test of consistency given the seventh seed's strengths lie in his willingness to rally from the baseline.
Djokovic tried to destabilise Simon with a number of drop-shots but they were poorly executed, with two in particular at the end of the second set helping Simon force a decider.
During his on-court interview after the match, a spectator shouted, "No more drop-shots!", to which Djokovic replied directly: "I hate to say it, but you're absolutely right."
The top seed later explained: "It's not easy when you're not feeling the ball well and when you're not moving that great.
"When you're playing someone like Simon, he senses that and he makes you play an extra shot.
"Then you're trying to cut down on the length of the rallies, go for a winner or go for a drop-shot. Sometimes you have a brain freeze, if I can call it that way."
Djokovic raised his game in the fifth set, breaking twice to take a 5-1 lead before serving out victory after four hours and 32 minutes.
Nishikori's work-out was far less strenuous as he beat France's Jo-Wilfried Tsonga 6-4 6-2 6-4 in less than half the time, two hours and two minutes.
"I'm sure I'll be fine," Djokovic said. "I've had worse situations where I had much less time to recover after long matches."
Nishikori, ranked seventh in the world, has lost all of his last four meetings with Djokovic and is under no illusions about the scale of the task ahead.
"The biggest thing is he doesn't miss," Nishikori said, "He doesn't give you any free points. I have to be the one who dictates."
World number six Tomas Berdych is also safely through to the last eight after he came through his own five-setter against Spain's Roberto Bautista Agut.
Berdych lost the first set on Margaret Court Arena but outlasted Agut to win 4-6 6-4 6-3 1-6 6-3.
Source: PA
