• World No1 withdraws before his quarter-final because of knee injury • ‘It’s not about London, it’s about the longer term,’ says Spaniard

Rafael Nadal’s participation at the ATP World Tour Finals in London this month is in major doubt after the world No1 pulled out of the Paris Masters with a knee injury.

Rafael Nadal’s victory at Paris Masters ensures he will end 2017 as world No1 Read more

The Spaniard had previously insisted he still expected to play at the year-ending tournament despite heavy strapping on his right knee during his last-16 win over Pablo Cuevas on Thursday.

However, in a press conference on Friday, Nadal admitted he could be forced to take an extended break. The Spaniard has been plagued by knee injuries during his career. “I have to pull out,” said the 10-time French Open champion. “Of course it’s a very tough decision for me, especially here in Paris, which has been the most important city in my career without a doubt. It’s a tough situation but I tried my best. I did one treatment yesterday night to try and play today.”

After wrist problems badly affected his 2016 season, Nadal had stayed fit throughout a remarkably successful 2017 campaign, winning two grand slam titles and returning to the top of the rankings. But knee problems, which have dogged his career, resurfaced in Shanghai last month, causing him to miss last week’s tournament in Basel.

Nadal, who has never won the Paris Masters, did not know whether he would be fit for the ATP finals, which begin on 12 November.

“It’s not about London, it’s about the longer term,” he explained. “It’s important to play tennis as long as possible. The knee is always bothering me a little bit but sometimes it’s worse.” Guardian sport