PIX: Lehecka stuns Auger-Aliassime; Tsitsipas survives scare

Images from the men's singles fourth round matches at the Australian Open, on Sunday.

Tsitsipas holds off Sinner in thriller

Stefanos Tsitsipas found another gear when it counted to fend off Jannik Sinner in a five-set thriller and reach the Australian Open quarter-finals in a rare win for the high seeds on Sunday.

A year after dumping Sinner out in the quarters at Melbourne Park, third seed Tsitsipas crushed the Italian's hopes of a great escape as he held firm to complete a 6-4, 6-4, 3-6, 4-6, 6-3 victory at a heaving Rod Laver Arena.

With the Greek dominated for two sets as Sinner roared back into the match, Tsitsipas captured the decisive break in the sixth game of the decider before sealing it in style with a cross-court forehand winner.

The three-times Australian Open semi-finalist will meet unseeded 21-year-old Czech Jiri Lehecka for a place in the semi-finals.

Unseeded Czech Jiri Lehecka toppled sixth seed Felix Auger-Aliassime 4-6, 6-3, 7-6(2), 7-6(3) to reach the quarter-finals of the Australian Open on Sunday, as the exit of yet another big name left the Grand Slam thin on star power for its second week.

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 quarter-final, 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.

Korda outlasts Hurkacz to reach first Grand Slam quarter-final

American Sebastian Korda reached the quarter-finals of a Grand Slam for the first time on Sunday after defeating Poland's Hubert Hurkacz 3-6, 6-3, 6-2, 1-6, 7-6(10-7) at the Australian Open.

Korda, who dumped 2021 and 2022 runner-up Daniil Medvedev out in the third round, got off to a shaky start on Rod Laver Arena against 2021 Wimbledon semi-finalist Hurkacz but the 29th seed bounced back to take the second and third sets.

Hurkacz, seeded 10th, grabbed the fourth set and earned two break-points at 5-5 in the fifth but Korda kept his calm to escape the trouble before they headed into a tie-breaker.

Korda raced to a 7-3 lead in the tie-breaker after winning six consecutive points but Hurkacz came fighting back to level it at 7-7.

Korda did not panic and closed out the victory with a backhand winner after nearly three and a half hours on court.

"It feels awesome. I was not feeling too much energy towards the fourth and fifth sets but you guys (the crowd) picked up me," Korda said in his on-court interview.

"I tried to stay as calm as I possibly could ... it was difficult but I am very happy with the way I kind of just stayed down and kept going through. The outcome was great."

The 22-year-old, who will face Karen Khachanov in the quarter-finals after the Russian knocked out Japan's Yoshihito Nishioka in straight sets, said he became superstitious in the tie-breaker.

"I got a little superstitious with the towel. The towel got me through it," he laughed. "Every time I went to the towel I won the point, so I just kept going to it - my new friend."

Korda is just the third American to reach the quarter-finals at the Australian Open since Andy Roddick last accomplished the feat in 2010. Tennys Sandgren (twice) and Frances Tiafoe have also reached the last eight since.