His first title in 2008 was followed by a knee injury-enforced absence 12 months later.

In 2010, he was Wimbledon champion for a second time before finishing runner-up to Djokovic the following year.

Things then got steadily worse with a second round exit against Lukas Rosol in 2012, sparking a seven-month absence from the tour as his knee problems flared up again while, in 2013, he was dumped out in the first round by Belgian journeyman Steve Darcis.

That was the only time Nadal has ever exited a grand slam in the first round.

“I am going to Halle on Monday [for the grasscourt warm-up event in Germany]. I want to try to play well at Wimbledon again,” said Nadal.

“I am healthy, that’s the most important thing. I hope my knee will have a positive feeling on grass because I felt my knee was better last year on the other surfaces.

“Grass is always a little bit harder for me after injury. I played Wimbledon in 2012 with my knee injury and I never played another match after. Last year I tried but I was not ready enough to compete.

“Let’s see how are my feelings this year because it’s a very important tournament.”

After his loss to world number 135 Darcis last year, Nadal came under pressure to skip future grasscourt seasons if he wanted to prolong his career.

One of those urging him to rethink was three-time Wimbledon champion Boris Becker, who has since gone on to join Djokovic’s coaching set-up.

“He definitely has to consider whether grass has a future for him,” said Becker at the time.

“Grass is very different compared to the other surfaces. Your movement is different and you have to have healthy legs because you’re changing direction, you’re slipping and sliding.

“If you have a knee problem, grass is the worst surface. Hard courts are not as bad because you have a firm position, you can put your foot down and stand up to hit the ball – the bounce is higher so you don’t have to bend as low.”

Even Nadal admits he is unsure over how he will fare in Halle, where he is top seed after skipping the tournament last year.

“I know probably the result will not be the perfect one because the days of preparation are not the right ones. And after how tough the match was today physically, I will be more tired.”

Nadal, who has pulled level with Pete Sampras on 14 majors and now stands just three off the all-time record held by Roger Federer, also believes his fifth successive French Open win was the sport’s payback for his loss to Stan Wawrinka in the Australian Open final.

Again, his challenge was hobbled by injury – this time by back trouble.

He said that his roller coaster form in the pre-Roland Garros claycourt season, when he lost three matches for the first time in a decade, was a direct result of that shattering loss in Melbourne.

“Stan played amazing, I don’t know if I would have been able to beat him. But I didn’t compete in that match and that was hard to accept.

“I had a few months where I went down mentally. I was fighting but didn’t feel strong enough. But for the last month, I had my motivation and positive feelings on court again.”