World No.2 Rafael Nadal has crashed out of the Australian Open after losing to Greece’s Stefanos Tsitsipas who became only the third player to defeat the 20-time Grand Slam champion while two sets down.

After clinching the first two sets, Nadal appeared well on his way to a 35th grand slam semi-final until the Greek No.5 found his wings.

Tsitsipas said he was left “speechless” after coming back from two sets down to take out their quarter-final at the Australian Open on Wednesday night.

It’s been deemed one of the sport’s more extraordinary comebacks, with Tsitsipas saying he surprised himself with how he managed to dig himself out of a seemingly insurmountable deficit.

Tsitsipas pinched the third set in a tiebreak to go on to win the tournament.

It marked just the second time in Nadal’s 19-year grand slam career that he’d lost a match after being two sets up, the only other occasion coming against Fabio Fognini at the 2015 US Open.

He’d lost one other Masters series match against Roger Federer the same way.

“I flew like a little bird – everything was working for me,” Tsitsipas said after the Rod Laver Arena match in which he claimed a 3-6 2-6 7-6 (7-4) 6-4 7-5 win to set up a last-four match with Daniil Medvedev.

Tsitsipas celebrates after beating Nadal during day 10 of the Australian Open. Photo: Getty

“It’s an unbelievable feeling to be able to fight on such a level,” Tsitsipas continued.

The loss leaves Nadal equal with Federer on 20 grand slam wins, with Novak Djokovic moving to 18 if he is victorious at Melbourne Park for the ninth time.

“Of course (I’m ) sad,” Nadal said.

“I lost a match in the quarter-finals of an event that means a lot to me.

“The Australian Open is one of my favourite events, without a doubt. So I missed an opportunity to be in the semi-finals again.”

Dylan Alcott reigns supreme

Meanwhile, on early Thursday morning, Dylan Alcott won the quad wheelchair men’s singles Australian Open title for the seventh straight time.

Alcott poses with the championship trophy after winning his Quad Wheelchair Singles Final match against Schroder. Photo: Getty

It took him just over an hour to score his 12th Grand Slam title, defeating Dutchman Sam Schroder 6-1, 6-0.

Their tournament had to be relocated to Margaret Court Arena because Nadal and Tsitsipas’ match stretched into a fifth set on Rod Laver Arena.

“I feel very lucky to be doing my job right now, even though it’s 12:45am,” Alcott said in a post-match interview.

“But I’ll play at 3:00am in the carpark to be honest because it’s a privilege to come out here every time and get an opportunity to play the Australian Open.”

Asked about his next big aim, the 30-year-old said he was desperate to shoot for gold at a rearranged Paralympic Games in Tokyo this year.

“Once, every four years people with disability are the stars,” smiled Alcott.

-with AAP