Australian teenager Thanasi Kokkinakis is savouring the biggest win of his career, a shock first-round defeat of world No.13 Ernests Gulbis that has sent local hopes soaring.

Only German Phillip Kohlschreiber can stop Australia from having a local man in the second week of the tournament after Kokkinakis’s pulsating 5-7 6-0 1-6 7-6 (7-2) 8-6 win over Gulbis set up a dream second-round clash with Sam Groth.

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The winner of the Kokkinakis-Groth match will take on either fellow Australian Bernard Tomic – or Kohlschreiber – for a spot in the last 16 at Melbourne Park.

Living up to his reputation as one of the next big things in tennis, Kokkinakis saved four match points – and fought off 10 successive break points in the final two sets – to take down Gulbis in a four-hour thriller on the opening night.

“Best win of my career,” Kokkinakis said.

“I beat a guy that made the semis of the French Open (last year).

“He was up in the fourth, I think two-love, but I kept making him play balls.

“I’m really happy with how I stuck together. Even though I thought for a lot of the period of that time I wasn’t playing my best tennis, I found a way to kind of get the points there, the games I needed to.

“It was exciting. I know it was a good win. There’s more to come.”

The 18-year-old’s stirring win preceded his best mate Nick Kyrgios’ five-set triumph over Argentine Federico Delbonis and gave Australia its best start to the Open in 12 years.

All up, seven Australian won on day one, with Tomic, Groth, Marinko Matosevic, James Duckworth and Jarmila Gajdosova also advancing.

“There’s so many names right now, so it’s just an exciting time,” Kyrgios said after his 7-6 (7-2) 3-6 6-3 6-7 (5-7) 6-3 victory, adding that he fed off Kokkinakis’ spirited win on neighbouring show court three.

“When I saw him win on the scoreboard, it gave me a little bit of motivation.

“I was just real happy for him.”

Kokkinakis and Groth, who beat Serb Filip Krajinovic 6-3 7-6 (7-4) 6-4 for his first Open win, are almost certain to meet in the feature night match at Rod Laver Arena on Wednesday.

“It’ll be great,” Groth said.

“Obviously it makes it difficult for the crowd, you know, where their allegiances lie and that sort of thing.”

– AAP