Rafael Nadal has pulled out of the ATP World Tour Finals in London after the ongoing issues with his knee flared up during his first round robin match against David Goffin.

The Spaniard, who was bidding to win the season-ending event for the first time in his career, suffered a shock loss as he was beaten 7-6, 6-7, 6-4 by the Belgian, but it was clear in the final stages of the match that he was struggling to cope with his knee injury.

Nadal confirmed his decision immediately after the game and the world number one will now focus on getting fit for the start of the 2018 campaign. The 31-year-old has had a successful campaign having won six titles including two Grand Slams — the French Open and the US Open — but the season's exertions seem to have caught up with the Spaniard.

The 16-time Grand Slam champion's participation in London was in doubt before the start of the event after he had pulled out midway through the Paris Masters earlier in the month. Nadal was confident that he can pull through and play at his best but it was not to be.

It is Nadal's sixth withdrawal from the competition in 13 years and he will now be replaced by compatriot Pablo Carreno Busta for the remainder of the event.

"My season is finished. Yeah, I had the commitment with the event, with the city, with myself. I tried hard. I did the thing that I had to do to try to be ready to play. But I am really not ready to play," Nadal said after his loss to Goffin, as quoted by Sky Sports.

"I cannot hold with enough power to keep playing. I tried, but seriously it was a miracle to be very close in the score during the match. It really doesn't make sense."

"Yeah, of course it's been a tough day. But I knew before the tournament that it was going to be a tough situation. I wanted to try, but it was not possible. I have to accept the bad news, bad feelings. It's the end of my season, but it's been an unforgettable one," Nadal told Sky Sports in the aftermath of his decision to pull out of the ATP Finals.

Rafael Nadal
Rafael Nadal withdrew from the ongoing ATP Finals in London after his loss to David Goffin on Monday (13 November) Getty