And Kyrgios' junior coach, Todd Larkham, says the 18-year-old has the ability to continue winning as long as his main weapon – his serve – isn't compromised by a fragile shoulder.

A jubilant Kyrgios spun his racquet around his forefinger like a gun-slinger after blasting a tournament leading 34 aces in his four-set victory over German and world no.81 Benjamin Becker 6-3, 6-7 (5-7), 6-2, 7-6 (7-2).

Kyrgios' next opponent will be 27 seed Benoit Paire, of France.

Doctors cleared Kyrgios of any need for surgery on his shoulder before the tournament, but the former junior world No.1 did require treatment on the joint during his match with Becker - no relation to former German star Boris.

It was Kyrgios' second grand slam win, having defeated former top-10 player Radek Stepanek in his French Open debut last year.

"This one I had to dig deeper a bit more, he played some incredible tennis," Kyrgios said.

"But I thought I served well when I needed to.

"Especially being injured the last couple months, it was really special, this win.

"I was feeling [the shoulder] a little bit, but that's normal. You're always going to carry a bit of a niggle. I thought it would be smart to get it worked on.

"It pulled up really well, it lasted four pretty tough sets – massive improvement from what it has been."

Recovery will be essential for Kyrgios, given his match was also played in temperatures over 40 degrees at Melbourne Park and he hasn't had many matches leading into the Australian Open.

"I'm just going to get in the ice bath, listen to music and chill out," Kyrgios said.

Kyrgios' big shots - particularly his serve - set up the win for the world No.183.

Along with his 34 aces, Kyrgios won 91 per cent of his first serves-in. That figure dropped startlingly to 44 per cent on his second serve.

The win guarantees Kyrgios $30,000, but Larkham said the payday could be bigger if his shoulder stayed strong.

"It depends on the shoulder a bit, because when he can't serve big he's vulnerable," Larkham said.

"But if he comes out and his shoulder's all good, he can serve big, it's a very winnable match [against Paire]."

"[Once he got treatment] he backed off on his serve for a couple games there, but once he got his serve back it was completely difficult. He relies on that weapon.

"If he can't play at his maximum power he's going to need to make a lot of first serves."

"His speed on the ball and the accuracy is as good as anyone in the tournament."

The most impressive feature of Kyrgios' win was his composure in the big points. At crucial stages he motioned with his arms to the crowd for support.

He conceded a break to trail 6-5 in the fourth set, before breaking back and storming home in the tie-breaker.

"I felt with the shoulder he would have struggled if it went to a fifth set," Larkham said.

"When it really mattered, when it came to the crunch he played his best tennis and that's the quality he's got."