The seemingly unstoppable Czech ace, Jiri Lehecka, stunned the tennis world on Sunday, as the unseeded player toppled the sixth seed Felix Auger-Aliassime in an incredible four-set match.

Lehecka battled back from a 4-6 deficit to win 6-3, 7-6 (2), 7-6 (3) and secure his spot in the quarterfinals of the Australian Open.

His victory marked the latest exit of a high-profile player, leaving the Grand Slam with a notable lack of star power as it enters its second week.

With holder Rafa Nadal and second seed Casper Ruud going out early, and other title hopefuls such as Daniil Medvedev and Alexander Zverev also exiting, a path was clearing for Auger-Aliassime to go deep at Melbourne Park.

But he ran into an inspired Lehecka, who beat 11th seed Cameron Norrie in the previous round. The Czech will play either Stefanos Tsitsipas or Jannik Sinner for a place in the semi-final and he said he is just getting started.

"The run is not over," Lehecka said. "All the guys I have beaten here are incredible and I've played my best tennis to show all the cards I have to beat them. It sounds crazy, but it's true and I'm happy to continue the journey."

Auger-Aliassime, 22, broke in the third game on the way to taking the opening set in 35 minutes but a huge momentum shift saw unseeded Lehecka take control.

After winning the second set to level the match, a delicate volley at the net helped Lehecka hold serve and set up a third-set tiebreak where he pounced on 2022 quarter-finalist Auger-Aliassime's errors to move ahead.

With a first Grand Slam quarterfinal and a first win over a top-10 player in sight, the 21-year-old Lehecka went up another gear in the fourth set tie-break to go up 6-3 before sending Auger-Aliassime out with a superb passing shot.

"Honestly it feels amazing," Lehecka added. "It's tough to find words because of what we've been through in the last year and coming back after losing the first round (in 2022).

"If someone told me I would play like this I would not believe them."