Andreas Seppi has suggested that Nick Kyrgios prevailed in their quarter-finals clash in the Australian Open because of his better serving display.

The pair battled out a five-set encounter in Melbourne, with Seppi surrendering a match point when two sets up against the 19-year-old Australian.

"Yeah, of course, I was a little bit down [after missing the match point]. Also the energy after the fourth set, you know, was a little bit down," Seppi told the tournament's official website.

"But, yeah, I think in the middle of the fifth set then we played again some good tennis. He served well in important moments. That was the key. That's why he won, I think."

Kyrgios becomes the first Australian player to reach a male's singles quarter-final at the tournament since Lleyton Hewitt in 2005.