“Actually, it gives me great joy to know that I can’t get worse than that, than what I played today,” he smiled. “I was obviously pleased to win the match, but in terms of the performance itself, I haven’t done well at all.

READ MORE: SERENA SERVES UP GLAMOUR CLASH WITH SHARAPOVA

“Gilles Simon is one of the best counter-punchers on the tour and he likes to play long matches.

“I knew what to expect on the court. But I honestly didn’t expect to make this many unforced errors. It’s a match to forget for me.”

The statistics make uneasy reading for the proud world No 1.

An astonishing 100 unforced errors, split between his forehand and backhand, prompted the Serb to say: “I don’t think I’ve had any close number to 100. But there is a first time for everything.”

Djokovic also blamed a “brain freeze” for continually trying to make drop shots, which either found the net or were run down by the athletic Simon.

“Sometimes you have a brain freeze, if I can call it that way. That’s what happened to me many times with those drop shots,” he said.

“I’ve been in these situations before. The good thing about grand slams is that you have a day off in between, which gives you enough time,” he said.

“I’ve had worse situations where I had much less time to recover after long matches. So I’m sure I’ll be fine.”

In making the quarter-finals for the 27th straight grand slam, Djokovic equalled Jimmy Connors in second place for the most consecutive last-eight appearances at the majors.

Earlier, Nishikori crushed Jo-Wilfried Tsonga in straight sets 6-4, 6-2, 6-4 while Tomas Berdych outlasted Spain’s Roberto Bautista Agut 4-6, 6-4, 6-3, 1-6, 6-3 to go into a quarter-final against Roger Federer.

Federer, in his late match, raced through a 6-2, 6-1, 6-4 victory against David Goffin in just 88 minutes.