Australian Open organisers faced criticism over scheduling after a long quarter-final between Novak Djokovic and Taylor Fritz delayed the night session by more than two hours.

Djokovic battled past his American opponent 7-6 (3) 4-6 6-2 6-3 after three hours and 45 minutes, with the match starting later than expected because of Coco Gauff’s lengthy clash with Marta Kostyuk in the opening match of the day on Rod Laver Arena.

Extending the tournament to 15 days this year and scheduling only two matches in each day session was meant to avoid the sort of early-morning finishes that have become increasingly common.

But there have only been two days out of 10 so far where play has finished by midnight, and Daniil Medvedev and Emil Ruusuvuori played until 3.39am in their second-round clash.

Tuesday’s delay meant women’s defending champion Aryna Sabalenka did not start her match, which had been due to begin at 7pm, until 9.10pm, and Jannik Sinner and Andrey Rublev were not hitting their first balls until after 10.40pm.

It is Sinner who will face Djokovic on Friday after he claimed a 6-4 7-6 (5) 6-3 victory at 1.22am.

Discussions took place about potentially moving one of the night session matches to a different court, but that ultimately did not happen.

Fritz said: “It just screws up your whole clock. I pray for those guys. I get it, matches go long some days. Like, today in particular, my match was long, the match before us was really long.

“But there’s got to be something they can do where people aren’t playing until 2, 3am, because I don’t think people really fully understand how much time we actually have to spend doing stuff after we finish playing. If you finish at 2am, there is no chance I’m going to sleep until 5, 6am.”

Wimbledon is unique in having an 11pm curfew, but play at the other grand slams has no cut-off point, and, with the average length of matches increasing markedly in recent years, what was rare in now commonplace.

Djokovic said: “We’ve seen in the past some late finishes. And I know for the crowds and for the tournament in a way it’s kind of exciting to see a 4am finish, a 3am finish. I was part of some of those. But it’s definitely not fun for us.

“The good thing about the quarter-finalist on the men’s section is we have two days. So I think that’s plenty of time to get a good sleep and recover.”

Djokovic will also need time to recover after battling past Fritz and into the semi-finals in Melbourne for the 11th time.

The world number one has never lost here once he has made it beyond the last eight, and there is no doubt how much he wants a 25th grand slam title.

Djokovic had beaten American Fritz in all eight of their previous meetings but this was certainly not straightforward. The first game alone lasted 16 minutes and the first set 84 minutes as they toiled in the heat.

Fritz, looking to reach a slam semi-final for the first time at the third attempt, remarkably saved all 15 break points he faced in the opening two sets, and he impressively levelled the contest.

It was just the third set he had won against the Serbian, with the other two both coming in a third-round clash here in 2021, when Djokovic suffered an abdominal injury but still managed to win in five.

But Djokovic began to turn the screw in the third set as Fritz started to feel his left foot, and successive breaks in the fourth set him on the way to a record-extending 48th slam semi-final.

Speaking to Nick Kyrgios on court, Djokovic said: “I suffered a lot in the first couple of sets. Also due to his high quality tennis. He was really kind of suffocating me from the back of the court.

“It was really difficult to find the right timing, it was really hot while the sun was still out. We all know Taylor has got one of the best serves in the world. I knew the kind of a threat he poses when he serves on such a high quality.

“Conversion of the break points was really poor but I managed to break him when it mattered. I think I upped my game midway through the third set all the way through to the end.”

Fritz was left with mixed feelings, saying: “I played a really high level for the first two sets, and they were a physical, tough two sets. It was like two and a half hours by the time we finished the two sets. I need to get to the point where I can do that for five hours.”

Sinner is the only player in the men’s draw yet to drop a set, with the Italian coming from 5-1 down in the second-set tie-break before sealing victory against Rublev, who is the first man in the open era to lose his first 10 grand slam quarter-finals.

Sinner believes he will be able to recover fully ahead of Friday’s match, saying: “Obviously it’s late now, by the time I get to sleep. But tomorrow I’m going to hit half an hour, 45 minutes, really late in the day, just to touch the ball a little bit.

“Then after, trying to sleep as much as possible, trying to recover. And that’s it. I feel quite confident that my body is going to recover in the best possible way.”