LONDON, United Kingdom (AFP) — Novak Djokovic battled through Wimbledon’s longest-ever quarterfinal to beat Felix Auger-Aliassime in a five-set epic on Tuesday as the former champion set up a titanic clash with defending champion Jannik Sinner.

Djokovic defied a calf injury suffered in the first set to win 7-6 (12/10), 3-6, 6-3, 6-7 (4/7), 7-6 (10/4) in a Centre Court classic lasting five hours and 15 minutes.

The indefatigable 39-year-old will meet world number one Sinner on Friday for a place in the final.

While Sinner beat German veteran Jan-Lennard Struff in straight sets on Tuesday, Djokovic had to dig much deeper before he subdued Canadian third seed Auger-Aliassime in one of the all-time gutsy Wimbledon performances.

The question now is whether the Serb will have anything left in the tank to beat Sinner.

Asked how he saw off Auger-Aliassime, Djokovic said: “With racket and a lot of heart. I have management of the nerves and the extreme tension you feel in these kinds of matches.”

“Towards the end, it was really anyone’s game. What can I say, these are the kind of moments that I still play tennis for, for sure.”

“I was telling the kids to go to sleep; I’m glad they stayed because it was one of the best matches I was part of on this court in my career.”

Djokovic has advanced to a record-extending 15th Wimbledon semi-final and 55th at the Grand Slams.

He is into the Wimbledon last four for an eighth consecutive time, setting a new record ahead of Roger Federer for the longest streak of men’s singles semi-final appearances at the All England Club.

Djokovic is only the second player in the Open era to reach the men’s semi-finals at Wimbledon aged 39 or older after Ken Rosewall in 1974.

Sinner wasn’t at his best against Struff, but his booming serve kept the world number 74 at bay as he reached his 10th Grand Slam semi-final and third at Wimbledon.