Ivo Karlovic is plotting to reprise his role as grand slam spoiler and scupper Nick Kyrgios’ Australian Open hopes on Wednesday.

Turning 36 next month, Karlovic is the oldest man in the singles draw.

But his victory over world No.1 Novak Djokovic in Doha two weeks ago should serve as a warning to Kyrgios that the Croatian giant will take a power of stopping at Melbourne Park.

If Kyrgios needs further reminding how dangerous the 23rd seed can be, he can ask Lleyton Hewitt.

In 2003, Karlovic delivered Hewitt the indignity of being the first defending champion in professional tennis history to be ousted in the first round at Wimbledon.

Twelve years on and Karlovic says he’s used to playing the villain role, happy to take out the crowd favourites at the big events.

“After all these years, it’s not so intimidating,” he told AAP.

“I’ve been around for a very long time and I’m happy that I was still able to do it.

“He’s an Australian, so it’s always going to be important for you guys that he does well here.

“He’s a young guy and I’m old, so it’s a clash of young against old.

“We’ll see how it goes. I don’t feel any pressure. I’m just here to enjoy tennis.”

Kyrgios may be well known to most following his stunning win over Rafael Nadal at Wimbledon last year, but Karlovic said he hadn’t watched the teenager until Monday night.

“I’ll look a little bit more now and hopefully I can find some weaknesses,” Karlovic said.

Kyrgios knows he’ll have his work cut out.

“He’s obviously one of the best servers on tour,” he said.

“Has been for a long, long time. With age, he seems to be hitting spots better.”

Victory for Kyrgios would advance the Australian No.1 to a very winnable third-round match against either Tunisia’s Malek Jaziri or Frenchman Edouard Roger-Vasselin.

But with his five-set first-round match against Argentine Federico Delbonis finishing after midnight on Monday, Kyrgios said his immediate focus was on rest and recovery.

The Wimbledon quarter-finalist is among seven Australians chasing a third-round spot on Wednesday.

Best mate Thanasi Kokkinakis plays Sam Groth in an all-Australian affair, James Duckworth confronts French 24th seed Richard Gasquet, Bernard Tomic takes on German 22nd seed Bernard Tomic and Marinko Matosevic meets Scottish sixth seed Andy Murray.

In women’s action, Jarmila Gajdosova says she has nothing to lose against Romanian third seed Simona Halep.