Nick Kyrgios is vowing to fight through the pain barrier after revealing he’ll rely on cortisone to get through the Australian Open starting next Monday.

Australia’s big hope is battling a knee injury that led to a quickfire straight-sets loss in his third and final match at last week’s Hopman Cup in Perth.

The 2015 Open quarter-finalist said he planned to still participate in Monday night’s Fast4 exhibition event in Sydney to test out his injury.

“I’m getting some sort of cortisone thing but it’s not an injection,” Kyrgios said.

“I’m doing everything I can for it. I have three more treatments left. Tonight is a bit of a test run to see how it’s feeling.”

Kyrgios carried a hip injury into the US Open in September, only to quit his third-round match against Ilya Marchenko.

The 21-year-old world No.14 upped his training during the summer to try to avoid similar setbacks but is now racing the clock to be 100 per cent for his home slam.

“I’m going to lay it all on the line in Melbourne. Whether it hurts or not, I’m going to push it to the limit,” Kyrgios said.

“Obviously the grand slams are the tournaments me and (fellow Australian) Bernard (Tomic) tend to step up and that’s where we like to play.

“I’m going to try and leave it all out there and whether it’s hurting or not. It’s really not going to affect my game.”

Kyrgios will need ‘luck’, says Cash

Two-time Open finalist Pat Cash says Kyrgios must blow his early-round opponents away if he’s any chance of breaking Australia’s 41-year men’s title drought in Melbourne.

“I’ve always felt that to have success in a slam you need a bit of luck and if Nick’s got a niggling injury he wants to get through the first rounds as quickly as he possibly can,” Cash said.

“A long five-set match can make life tricky.”

Cash said a key to the success and longevity of four-time champion and former world No.1 Roger Federer was his ability to blitz early-round opponents.

“He’s got the sort of game that can blow players away and Nick is developing it,” he said.

“Getting through the early matches quickly is going to be a big advantage to someone like Nick if he’s carrying a injury.”

Cash himself carried a shoulder injury into the 1987 final, losing in five sets to Swede Stefan Edberg.

“I always say this is the one that got away,” the 51-year-old said.

-AAP