The 10-time Grand Slam champion battled for four hours, 32 minutes before winning 6-3, 6-7 (1/7), 6-4, 4-6, 6-3 and will now play Japan's Kei Nishikori in the last eight.

It was a gruelling win for Djokovic, who committed a staggering 100 unforced errors before finally subduing the dogged French 14th seed, who was a constant menace in the Rod Laver Arena thriller.

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.

It will be the Serb's 35th overall Grand Slam quarter-final appearance, and he has reached the last eight in Melbourne for a ninth consecutive year.

It was Djokovic's first five-setter since beating South Africa's Kevin Anderson in the fourth round of Wimbledon last year.

While Djokovic won his 10th straight match over Simon, he only did so after a monumental struggle, losing his serve four times and often looking anxiously at coach Boris Becker in his player's box.

Simon's only win over Djokovic was in their first meeting in Marseille in 2008, but his patient probing rattled the game's top player.

The five-time Australian Open champion's composure was tested by the counter-punching Frenchman, who was content to keep in long rallies and wait for errors.

The first set lasted 58 minutes as Djokovic broke in the eighth game and then took the set on his fourth set point.

The world number one's frustrations were palpable in the second set as he missed 11 break point opportunities before dropping his first set of the tournament in a tiebreaker, with Simon getting three mini-breaks.

It ended a sequence of 26 consecutive sets won by Djokovic, going back to the ATP World Tour finals in November.

It was hard going and compelling viewing, and Djokovic got the crucial third set in 47 minutes when Simon netted a backhand to lose his serve.

In the fourth set, Simon continued to frustrate Djokovic's attempts to kill off the match as the Serb's tally of errors continued to mount.

The persistent Frenchman broke Djokovic in the ninth game and took the match into a fifth set amid another flurry of Djokovic errors.

Djokovic got two service breaks in the fifth game only to be broken back once, but he finally clinched victory on his third match point with a backhand winner.