World No.1 Novak Djokovic has survived a gruelling four-set slugfest against German Alexander Zverev to secure a place in his ninth Australian Open semi-final.
The eight-time Open champion recovered from breaks down in the third and fourth sets to conquer sixth-seeded Zverev 6-7 (8-6) 6-2 6-4 7-6 (8-6) in a high-quality match lasting three-and-a-half hours at Melbourne Park.
Djokovic will now meet Russian qualifier Aslan Karatsev, who is making a fairytale run on his grand slam debut, in a David vs Goliath final-four match-up.
The 33-year-old, who has expressed concerns about an abdominal strain throughout the tournament, often became frustrated during the contest, which finished in the early hours of Wednesday morning.
In a fiery moment, Djokovic destroyed a racquet after failing to return a speedy Zverev serve when down in the third set, earning him a code violation for racket abuse.
He eventually dropped the game to fall behind 4-1 but the release of frustration sparked Djokovic’s comeback to claim the set.
Since demolishing Jeremy Chardy in the first-round, Djokovic has spent more than 12 hours on court as he chases his 18th major title, which would put him just two behind Roger Federer’s record of 20.
In an ominous sign for his rivals, including world No.2 Rafael Nadal, Djokovic has won the first major of the year every time he has qualified for the semi-finals.
The result continues Zverev’s drought of having never defeated a top-10 opponent at a grand slam.
The 23-year-old had a set-point in the fourth, but was unable to take the match into a deciding set as Djokovic pulled off a remarkable victory.
“I served extremely well. I think I had a slightly more aces than him which is a miracle playing against a big server like Sascha (Zverev),” Djokovic said.
“Down to the last very last shot, it was anyone’s game.
“A lot of nerves out there, a lot of pressure and emotionally I feel a little bit drained, honestly. It was a great battle.”