Nick Kyrgios rocketed into contention for a wildcard into the main draw of the Australian Open on Monday, beating top-seed Sam Groth 6-4, 6-2, 3-6, 6-3 in the play-off tournament.
The Canberra teen got off to the best of starts when he broke serve in the opening game, unsettling Groth who holds the world record for the fastest serve, at 263km/h.
''Obviously I'm pretty stoked with that performance,'' Kyrgios said after the two-hour, 19-minute match. ''I knew I had to play some of my best tennis to get the win today.
''I was fortunate enough to get the break in the first game. I think I returned pretty much every first serve, so that gave me a lot of confidence for the whole match to break him.''
Having held strong on his own serve, Kyrgios took the first set, and when he brought up three break points in Groth's second service game of the next set, the Canberran took a psychological edge
''I thought I was getting a little bit under his skin because little things were bothering him, and I knew he was panicking a bit,'' Kyrgios said. ''So I knew if I just stayed strong, I was going to be fine.''
However, a shift in momentum in the third set saw Groth back in the action.
''When I lost the third set, I was obviously pretty disappointed because I had a lot of break points and couldn't take them,'' Kyrgios said. ''But I knew if I just slowed down the game and served well, I was a shot in the fourth.''
Kyrgios showed no signs of the knee problem that has plagued him in recent weeks, despite entering the tournament after winning the Australian 18s singles and doubles titles on the weekend.
''I was battling a bit at the end, but I knew I was so close to winning,'' he said.
''I had a lot of break points in the fourth and I ended up taking one and it just went from there.''
Kyrgios' quarter-final opponent on Wednesday is eighth-seed Matthew Barton, who beat South Australian Thanasi Kokkinakis in four tough sets.
Ashley Keir will be looking to replicate Kyrgios' upset on Tuesday when she takes on the No. 2 seed Ashleigh Barty in the women's draw.
Keir was on her way back to Canberra from the Australian 18s tournament on Sunday when she received an unexpected wildcard entry into this tournament.
''To draw Ashleigh Barty is going to be an awesome experience,'' Keir said.
''Ash has had a pretty good year this year, so it will be great to see where I sit with her.
''I have no pressure on me, I can just go out there and whatever happens happens. She's expected to go pretty far in this tournament , and I have no expectations at all.''