World number one Novak Djokovic says he is risking further injury by continuing to play in the Australian Open.

Djokovic who has been struggling with an abdominal injury, said: “As long as I’m with a high dose of painkillers, I can bear some of the pain.

“It’s kind of a gamble, that’s what the medical team told me.”

The Serb slipped during Friday's third-round win over American Taylor Fritz. Despite limping and needing courtside medical attention, he won in five sets and called the win “one of the most special in my life”.

He then defeated Canada’s Milos Raonic on Sunday, although one side of Djokovic’s chest was heavily strapped up.

“The level of the pain was bearable, but I managed to find a way to win,” he said.

“It could cause much more damage. That’s something I won’t know until I stop taking painkillers as they hide what’s happening, so you might not feel it, but then the big damage might be done.

“There’s a slight chance I will make significant damage that would take me out of the tour for some period.”

Djokovic has a 5-2 record over Zverev, whose two victories saw him clinch the 2018 ATP Finals and the Rome Masters in 2017.

"I'm looking forward to the challenge,” said the US Open finalist. “It's one of the toughest challenges in our sport to be playing Novak at this Grand Slam in later rounds.

"I had two of my biggest wins against him, but the other matches were extremely difficult.”

Can ‘dangerous’ qualifier Karatsev cause another shock?

The first men’s quarter-final sees Bulgarian 18th seed Grigor Dimitrov play Russian qualifier Aslan Karatsev.

Ranked 114th, Karatsev advanced through three rounds of qualifying in Doha and has beaten Argentina’s eighth seed Diego Schwartzman and Canada’s 20th seed Felix Auger-Aliassime in Melbourne.

The 27-year-old, one of three Russians left in, is the first qualifier to make a Grand Slam last eight in a decade.

Dimitrov, 29, has lost in three Grand Slam semi-finals, including in Melbourne in 2017, but beat third seed Dominic Thiem in round four.

However, the Bulgarian said he would not be under-estimating Karatsev.

“You treat every player the same way and I will treat this match no differently,” said Dimitrov.

“He is playing great tennis, he’s a dangerous player and this is the quarter-final of a Grand Slam so you don’t take anyone lightly.”

Tennis Breakfast will be on BBC Radio 5 Live Sports Extra from 07:00 GMT on Tuesday and will include live commentary of the women's quarter-final between Serena Williams v Simona Halep from 08:00 and then commentary of the Djokovic v Zverev match.