The US Open champion looked to be heading out at the quarter-final stage before he rallied to claim a battling 6-7, 3-6, 7-6, 7-5, 6-4 victory on Rod Laver Arena.

The Russian, last year's runner-up, will face fourth seed Stefanos Tsitsipas for a place in the final after the Greek swept aside Italian 11th seed Jannik Sinner 6-3, 6-4, 6-2.

The winner of that tie will play either Spaniard Rafael Nadal, who is seeking a record-breaking 21st Grand Slam title, or Matteo Berrettini of Italy for the Australian Open crown.

"I was not playing my best and Felix was playing unbelievable, serving unbelievable, I didn't really know what to do, so I don't know if people will like it but I told myself 'What would Novak do?' - or Rafa or Roger to be honest, they won so many matches like this," Medvedev, the highest-seeded player at the tournament after Novak Djokovic withdrew following his deportation from Australia, said.

 "So I thought, 'Okay, I am going to make him work, fight to the last point'.

"It is a semi-final of a Grand Slam, so even if I am in the worst shape of my life I am going to fight my best and make it tough for my opponent.

"Stefanos is a tough player, we have had a lot of tough matches already."

In the women's draw, American Danielle Collins and Polish seventh seed Iga Swiatek will clash in the last four after they came through their respective quarter-finals.

Collins, the 27th seed who took a break from the sport last year, beat France's Alize Cornet 7-5, 6-1, while Swiatek edged out Estonian veteran Kaia Kanepi 4-6, 7-6 6-3.