Australian Open 2016: Novak Djokovic vs Kei Nishikori quarterfinal preview

Novak Djokovic kept his Australian Open title defense alive after escaping France’s Gilles Simon in five sets, but the world No. 1 could face another tough challenge when he meets a surging Kei Nishikori in the quarterfinal round.

Despite a sloppy game from Djokovic, who overcame a staggering 100 unforced errors, the Serb still managed to earn a spot in the quarterfinal round of the 2016 Australian Open at Melbourne Park after defeating Simon 6-3 6-7(1) 6-4 4-6 6-3. Djokovic said he expected Gilles to put on a show, but admitted his unforced errors played big in his ugly win in a match that lasted four hours and 32 minutes.

"Playing against a player like Gilles you can expect a lot of rallies," Djokovic said, reports the BBC. “I made a lot of unforced errors today but he was fighting, he was playing well, physically it was very demanding and I'm just happy to get through this one."

Djokovic, who is bound for his 27^th consecutive Grand Slam quarterfinal appearance and ninth successive Australian Open QF game, had to raise his game in the last set, racing into a 4-1 lead and serving the match on his second opportunity.

It was the first match Djokovic has dropped a set since a semifinal win over Stan Wawrinka at the Paris Masters in November and the first match in Melbourne he was pressured into playing five sets. However, the 10-time Grand Slam could be on another tight match against Nishikori, who breezed past France’s Jo-Wilfried Tsonga 6-4 6-2 6-4.

Nishikori, who took only two hours to dispatch an inconsistent Tsonga, has not dropped a single set in his first four matches at the 2016 Australian Open, but the seventh seed Japanese believes it would be different story against Djokovic.

"It's going to be tough,” Nishikori said, reports the Sydney Morning Herald. "Really happy to be in a quarter-final ... good recovery tomorrow and hopefully I can play another good match."

Nishikori has only won two of his eight matches against Djokovic including a semifinal round win at the 2014 US Open. But his impressive run at the first Grand Slam event of the year could serve him well against “Djoker.”