Melbourne, Jan 24 (IANS): Five-time Australian Open winner Novak Djokovic managed to shake off a dogged five-set challenge from 14th seed Gilles Simon on Sunday, despite the world No.1 playing one of his worst tennis matches in recent memory.

Djokovic hit an unprecedented 100 unforced errors throughout the match -- a self-proclaimed record number of mistakes -- which spanned a gruelling four hours and 32 minutes before he won 6-3, 6-7, 6-4, 4-6, 6-3, reports Xinhua.

Simon nagged the top seed the entire time, returning balls and waiting for the champion to make a mistake, with frustrations boiling over in a tense fourth set before the class of the Serb came to the fore in the fifth.

In his post-match press conference, Djokovic said he was pleased to win the match despite producing one of his worst on-court performances in recent years.

"Unfortunately you have days like this. It's actually good to win when you play that bad," Djokovic said.

"In terms of the level I've played, it's a match to forget for me."

When asked if he had ever hit 100 unforced errors in a match before, the five-time Australian Open winner said he had "never been close".

"But there's a first time for everything," he added.

Djokovic admitted he will need to step up his game on Tuesday, when he faces seventh seed Kei Nishikori, who dismantled world No. 10 Jo-Wilfried Tsonga in straight sets earlier on Sunday.