Melbourne VIC, Australia, 21 January 2015 | AAP

Nick Kyrgios has set his sights on a fourth-round Australian Open showdown with Swiss maestro Roger Federer.

The exciting 19-year-old delivered a calm and controlled performance to oust towering 23rd seed Ivo Karlovic 7-6 (7-4) 6-4 5-7 6-4 and move into the third round for the first time at Melbourne Park.

The big-serving Croatian sent down a stunning 40 aces, but Kyrgios wasn’t rattled.

While four-time champion Federer looms as a potential fourth-round opponent, Kyrgios must first get past Tunisia’s world No.75 Malek Jaziri, a five-set winner on Wednesday over Frenchman Edouard Roger-Vasselin.

Australia’s top-ranked man said he’d taken massive confidence from the win over Karlovic, who upset world No.1 Novak Djokovic this month in Doha.

Kyrgios, who has been hampered by back trouble and hasn’t had a win on the ATP tour since the US Open last August, said he felt much more comfortable on court after his five-set first-round win over Argentine Federico Delbonis.

“In the first round, there was a lot of expectation and pressure to do something.

“When I got past the first round it was the first win by me in a long time and it gave me a lot of confidence in my game.

“Physically backing up after five sets as well, I can take massive confidence out of that.”

Kyrgios said he knew he had to take the first set to stop Karlovic getting confidence and momentum with his big serve.

While he stumbled in the third, the vocal home crowd helped him to regain control.

The world No.53 relished the rowdy occasion but avoided the emotions that resulted in point penalty in round one.

“I thought the crowd was massive and they got behind me at some really key moments,” Kyrgios said.

Karlovic said he didn’t feel well in the opening two sets and struggled to get his giant frame moving around the court.

“If I had to use one word to describe it, probably horrible,” Karlovic said.

“In the first two sets, I didn’t move at all. It was really bad.”