Briton Cameron Norrie let slip a superb start as his ATP Finals debut ended in defeat by Norway’s Casper Ruud.

He ran away with the first set before Ruud hit back to win 1-6 6-3 6-4 and end Norrie’s semi-final chances.

The British number one will still face Novak Djokovic in a final group match in Turin on Friday.

There is only rankings points and prize money riding on the encounter with the world number one, who is already through to the last four following a 6-3 6-2 win over Russian Andrey Rublev earlier in the day.

But Norrie is still relishing the chance to face the 20-time Grand Slam champion for the first time.

“I can’t wait,” he said. “It’s another test for me and I’m going to go out and see if I belong and I can compete with a guy like that. I’m looking forward to the challenge ahead.”

Serb Djokovic will be joined in the last four by the winner of the match between world number eight Ruud and number five Rublev.

Playing at the elite tournament, which features the year’s eight leading male players, caps a successful year for Norrie, who won the prestigious Indian Wells tournament in October and has reached a career-high ranking of 12th in the world.

Norrie fails to make most of late call-up

Norrie has been in Turin all week, training and practising in case he got the call-up to play. So when he found out at lunchtime that Tsitispas had not shaken off the elbow injury that had hampered him in recent weeks, the Briton was ready to take to the court in the evening.

Perhaps with last month’s 6-0 6-2 loss to Ruud in the San Diego Open final still stinging, he got off to a blistering start.

Ruud had admitted to feeling nervous in his opening defeat by world number one Djokovic on Monday and there was still an awkwardness about the Norwegian early on in this match.

He said he had been thrown by the late change of opponent, explaining: “I woke up prepared for playing Stefanos and knowing I was the underdog and I could play freely and then you hear that he’s pulling out… so then kind of everything changed.”

But he settled down in the second set and made the most of a sloppy Norrie service game to break and then served out the set to level.

Ruud, 22, stepped up a gear in the decider and capitalised on Norrie’s increasing error count – the Briton had hit just three unforced errors in the first two sets but struck 17 in the third.

The decisive break came in the fifth game and although Norrie went on to save three match points, he could do nothing about the fourth.

“I wasn’t really getting the feel of his shots in the beginning and I made too many mistakes,” Ruud said. “I think for the first set and half the second he was the much better player out there. My serve saved me a little bit today.”

Norrie has enjoyed the best season of his career and having been ranked 74th at the start of the year, simply appearing at this tournament – which is second only to the Grand Slams in terms of prestige – is a huge achievement in itself.

He reached six finals this year, winning two titles, and while his tour season may be over he still has more tennis to play when he represents Great Britain at the Davis Cup Finals later this month.

“This week has been incredible for me so far,” Norrie said. “I was basically using it as a training block towards heading into the Davis Cup so obviously it was a bonus to get a couple of matches in there, and there was a lot to play for and huge for the experience as well.”

Does Djokovic now have time for some saxophone practice?

Top seed Djokovic, who is aiming for a record-equalling sixth title, said he was looking forward to facing Norrie on Friday and that the Briton “deserves to be here”.

“The good thing is that I qualified for semi-finals, so I won’t have that much pressure to win the match… but obviously every match matters, so I will go with the intention to win,” Djokovic said.

Since the pressure is off until the semi-finals on Saturday, the Serb may now have the chance to devote a bit more time to his new hobby – playing the saxophone.

“I do have it with me here,” he said. “I did not unpack it yet. It’s still in the bag due to the constrictions I have in the hotel, and I want to spare my wife and my team and everybody who is staying in the hotel.

“I want to spare them the terrible noise that comes out from my saxophone as I am a beginner, so I still have to learn.”

Salisbury on brink of semi-finals but Murray out

There were two other Britons in action on Wednesday in the doubles and they had mixed fortunes.

Joe Salisbury and American partner Rajeev Ram staged a brilliant comeback and saved two match points to put themselves on the brink of the semi-finals with a 6-7 (7-9) 6-0 13-11 victory over French duo Pierre-Hugues Herbert and Nicolas Mahut.

Victory in their final group match on Friday would put them through but they can also advance through a combination of other results.

But the result of the Salisbury/Ram match ended the hopes of Jamie Murray and Brazil’s Bruno Soares, who lost 6-2 6-4 to Colombians Juan Sebastian Cabal and Robert Farah earlier in the day.