Melbourne, Jan 22 (IANS): No.17 seed Jelena Ostapenko shocked seventh seed American Coco Gauff 7-5, 6-3 to sail through to the quarterfinals of the Australian Open for the first time in her career on Sunday.

Ostapenko, competing in her first Round 4 at the Australian Open, leveled her career head-to-head against Gauff to 1-1 with a 93-minute triumph in Margaret Court Arena, her first over a Top 10 player at a Grand Slam in three years, and the first Grand Slam quarterfinal appearance since 2018.

"My life changed a lot (after winning 2017 Roland Garros), so I needed a few years to really get used to what happened because I was really young. I was 19 and then turned 20," Ostapenko said. "I always knew and believed in my game. If I play well, I can beat almost anyone. I was trying to work more on my consistency, especially in the preseason. Yeah, just to step on the court and play my game. I think I'm doing it quite well this week."

The Latvian will next face reigning Wimbledon champion Elena Rybakina for a spot in the semifinals, after the Kazakh scored an upset of her own against World No.1 Iga Swiatek in their fourth-round match.

Ostapenko is 2-0 in her career against Rybakina, having only lost 11 games in two matches. Their last meeting came on grass last year in Eastbourne, a 6-4, 6-1 win for the Latvian before Rybakina went on to win at the All-England Club.

"It's going to be a hard match against Elena, but we played a couple of times, and I know how to play against her. I'm just going to try to focus more on myself and on my game, and hopefully I can bring the good and aggressive game again," Ostapenko said.

Gauff let six break-point chances go by in the first set after being the first player to break serve. She led 2-1, but Ostapenko broke back immediately for 2-2; from then on, the Latvian saved two break points as 2-2, and crucially, four at 3-3 -- including 0-40.

Gauff had two game points to force a tiebreak, but lost serve for a second time to fall a set behind. Ostapenko then saved the only break point she faced in the second set in the opening game.

The American was pushed past deuce in each of her first three service games of the set -- never facing break point -- before surrendering the decisive break in the eighth game.