Tennis legend Andre Agassi on Saturday backed misfiring Novak Djokovic to pull out of his form slump after he crashed out of the Australian Open.

Agassi, describing Djokovic as "one of the greats", said he could soon be back to his best, comparing the Serb's nosedive to his own troubles in the 1990s.

Djokovic, 29 and seeking a record seventh Australian Open title, suffered the worst in a run of upsets when he lost to 117th-ranked Denis Istomin in the second round.

"What I can speak to is Novak's game and his abilities and there's no reason in the world why he can't turn it around," Agassi told journalists by videolink. 

"Novak won't need to learn in as hard a way as I had to learn. He still has time, and he's a heck of an athlete. 

"In my opinion one of the greats of all time, so I give him a high chance coming back in a hurry."

Agassi battled back from injury, marital problems and, as he later disclosed, drug problems to re-launch his career in the late 1990s, winning five of his eight Grand Slam titles.

Djokovic's return to the top could face an obstacle in Andy Murray, who has replaced him as world number one and, according to Agassi, could now get even better.

"He's very impressive. I've always talked about Andy as a person that has never really realised his maximum potential," Agassi said.

"He's so good at certain things it almost makes him a bit indecisive. It almost makes him not bring his strengths to the table as much as he could.

"If he actually minimised his defensive skills by just five percent he might actually be a better player.

"My expectation is he is only going to get better. It looks like he's strong. It looks like he's fit. It looks like he knows how to invest in himself."

Agassi also had well-wishes for troubled Aussie Nick Kyrgios, who was booed off court and accused of not trying in a perplexing five-set defeat to Andreas Seppi in round two.

"He's obviously a rebel of sorts. He's a fighter of sorts. He might choose to take some of those fights and fight himself," Agassi said. 

"I would much prefer to see him fighting his opponent and fighting for the opportunity to get better and to do some of the things he's capable of.

"I wish good for him because he obviously isn't comfortable in his own skin at the moment."

Source: AFP