Dominic Thiem's incredible act of sportsmanship in Australian Open semi-final

Dominic Thiem has stunned fans and commentators with a remarkable act of sportsmanship for Alexander Zverev in their Australian Open semi-final.

The 26-year-old earned his first berth in an Australian Open decider with a courageous win over German Zverev on Friday night.

‘NOT A GREAT LOOK’: Fans stunned by 'embarrassing' delay in semi-final

Thiem had a slow start in their Rod Laver Arena clash but rallied for a 3-6 6-4 7-6 (7-3) 7-6 (7-4) victory in an absorbing encounter that lasted three hours and 42 minutes.

In a sign of the immense respect the two young guns have for each other, Thiem cost himself a point midway through the third set by telling Zverev he should challenge an incorrect call.

Alexander Zverev, pictured here thanking Dominic Thiem for the sporting display.
Alexander Zverev thanked Dominic Thiem for the sporting display. Image: Getty

After the linesman called a Zverev shot out, Thiem yelled out to his opponent and let him know he should send it to Hawkeye.

Replays showed the ball had caught the line, meaning Thiem lost the point because his preceding shot went out, and he also went on to lose that game.

Zverev turned and gave Thiem a thumbs up for his remarkable display of sportsmanship.

“Thiem is telling him to challenge,” a stunned Todd Woodbridge said in commentary.

“That was good, he is saying. Here comes the challenge. And it is... That is in. Thiem is going to give him the game.”

Can Thiem take down Djokovic?

Thiem will be out to dethrone the "king of Australia" when he takes on seven-time champion Novak Djokovic in the men's final at Melbourne Park on Sunday.

After losing the last two French Open finals to the king of clay, Rafael Nadal, Thiem is gunning for his first grand slam title but must get past seven-time Open champion Djokovic.

"He is the king of Australia, won seven titles here, more than any other man, so I'm always facing the kings of this grand slam in a final," world No.5 Thiem said.

"But I mean I try my best and of course I try everything to win."

Progressing for the first time past the fourth round in Melbourne, Thiem ousted Nadal in the quarter-finals to set up his final-four meeting with fellow young gun Zverev.

In a high quality affair, Thiem took control early in both tiebreaks which proved the difference.

He had three match points and while Zverev, playing in his first major semi-final, saved one, Thiem wouldn't be denied.

Dominic Thiem, pictured here celebrating his win over Alexander Zverev at the Australian Open.
Dominic Thiem celebrates his win over Alexander Zverev. (Photo by Recep Sakar/Anadolu Agency via Getty Images)

"It was an unreal match," Thiem said.

"Two tie breaks, so tough and so close - it was almost impossible to break him.

"But Australian Open finals is absolutely unreal."

Thiem admitted he was feeling nerves in a below-par first set with a place in the final on the line but found his groove to break early in the second.

He blasted an ace on set point to level at one-apiece before the match was bizarrely stopped for almost 10 minutes after roof lights went out behind the baseline.

Zverev, who had the best serving record of the tournament, hit the mark with a stunning 90 per cent of his first serves in the third set but Thiem produced 20 winners to stay in the hunt.

World No.7 Zverev had two set points on Thiem's serve at 4-5, but the pressure told with the German failing to convert either.

The Austrian got off a 3-0 lead in the tiebreak and gave himself three set points but only needed one with a searing backhand winner to take a two sets to one lead.

Squaring off in the youngest semi-final in a grand slam in 10 years, the pair went toe to toe in fourth set before Thiem again stepped up to secure his place in the decider.

with AAP