Rafael Nadal insists he remains determined to fight for titles at the “highest level” after his US Open defence ended in retirement.
The world No 1 was forced to stop his semi-final encounter against Juan Martin del Potro after losing the opening two sets 7-6 (7-3) 6-2 against the 2009 champion.
Nadal suffered a recurrence of his persistent knee injuries during a gruelling third round victory against Karen Khachanov and the problem became worse during the first set on Friday.
“I still have the passion for the game,” Nadal said.
“I am going to keep fighting and working hard to keep enjoying this tour and keep having chances to compete at the highest level. So that’s all.”
The Spaniard has suffered with tendinitis in his knee during his career and he spent eight months away from the game between 2012 and 2013
“The pain on the knee is always very similar,” he said.
“The problem is this time it was something a little bit more aggressive because it was in one movement.
“I know what I have. I know what is going on with the knee. The good thing is I know how I have to work to be better as soon as possible because we have a lot of experience on that.”
The 32-year-old won his 17th Grand Slam title at the French Open in June and has only lost four matches all year so far with two of those defeats coming through an injury enforced retirement.
“It’s not about losing. It’s about not having the chance to fight for it,” Nadal, who retired in his Australian Open quarter-final against Marin Cilic with a torn inner hip muscle, added.
“I have fought all my career against these kinds of things too. I have missed a lot of opportunities. It is tough, these moments. But at the same time I have to keep going and working hard to get more opportunities.
“I am playing the right way and enjoying things. I am having success at the age of 32. A lot of people in this room, including me, didn’t think I would be at this level at this age.”
Nadal dismissed the assertion that his body was more at risk of injury due to his game style, which relies on power and athleticism.
“All my career everybody say that because of my style, I will have a short career,” Nadal, who is three behind Roger Federer in Grand Slam titles, added.
“I am still here. I am still here because I love what I am doing.
While there was frustration for Nadal, victory for Del Potro saw the Argentinean return to a Grand Slam final for the first time in nine years when he memorably won the US Open aged 20, beating Nadal and Federer on the way.
“Of course it’s not the best way to win a match,” Del Potro said during his on-court interview.
“I love to play against Rafa because he’s the biggest fighter in this sport and I don’t like to see him suffering on court like today so I’m sad for him but I’m also happy to move forward.”
After fearing his career was over following a trio of operations to his injured left wrist, which forced him to miss the best part of two years, the 29-year-old returned and rebuilt his game.
At Indian Wells he won his maiden Masters 1000 title and reached Grand Slam quarter-finals at Roland Garros and Wimbledon prior to arriving in New York.
“It means a lot to me. I didn’t expect to get in another Grand Slam final. This is my favourite tournament, my biggest memories on a tennis court came on this court in 2009.”