For a man who loves football as much as tennis, the past week has been rough on Rafael Nadal, with Spain’s World Cup defence turning into what the 28-year-old describes as “a disaster”. Trying to win Wimbledon for a third time is his No1 priority but before he allowed himself to contemplate that thought, Nadal was keen to finish a heated argument with his uncle and coach, Toni.

Fingers were pointed and voices were raised as they discussed what had gone wrong in Brazil and who should and should not have played. In the confines of the locker room at the Hurlingham club in west London, it was a reminder of the passion that drives the world No1.

As he has done in the past four years, Nadal comes to Wimbledon as the French Open champion, having extended his record in Paris to a phenomenal nine wins in 10 years. Having won his second Wimbledon title in 2010, he lost in the final the following year and then in the second round, to Lukas Rosol, in 2012. Last year came the ignominy of going out in the first round to the inspired Belgian Steve Darcis, when Nadal was once again hampered by knee trouble.

“Last year, emotionally, was a little bit of a special year, because I came back after an injury of seven months, with the feeling that I was not recovered,” Nadal says. “That’s the real thing. I had to play the whole year with anti-inflammatories, every single match, so it was emotionally hard.

“There was a lot of success, it’s true, before Wimbledon but at the same time there was a lot of suffering. Every week was tough mentally because I had to resist, then I was having to playing with pain, then with anti-inflammatory injections.”

He adds: “After winning Roland Garros last year, probably emotionally, I went down a little bit after that. Last year, I was not 100% ready for the grass. I knew my knee was not perfect yet and grass is very aggressive for my knee because I need to play very low.

“But this year is a different story. Overall the feeling this year is better with my knee. I feel a little more comfortable running, and that’s very important.”

After the pain of 2013, Nadal seems happy, focused and determined to perform well. He does not, however, feel he has anything to prove. “No, the business is finished,” he says.

“When I won the first time, for me it was a dream come true, so that’s everything. I played five finals in a row – I didn’t play in 2009 – during that period I played great. I was able to win twice, I was able to be close against Roger [Federer] in 2007, too.

“When I started my career a lot of people said: ‘With his style, he won’t be able to play well on grass.’ That really motivates me even more. I always felt that I would be able to play well here if I am able to make the right preparation.”

Nadal won the title in 2008 – following an epic rain-delayed final against Federer that ended in almost total darkness – and again in 2010, victories that meant as much to him as any of his other 12 grand slam wins: “[I wanted to win] not only for other people,” he says. “I wanted to win it for me.”

After losing to Darcis 12 months ago, Nadal needed a break and a dodgy television signal while on a boat ruined his efforts to watch Andy Murray win the title. The pair have been good friends since they first met as juniors, and Nadal, who watched the match in full later on, was delighted by Murray’s victory.

“I was happy for him – he deserved to win,” Nadal says. “Even if the Olympics were very special, to win Wimbledon is so special for someone from Britain. And for him I know how important that was, especially after being in the semi-finals a few times and in the final the year before. I was happy for him and happy for Wimbledon, that there was a British player winning. I was happy for the British. They had waited a lot of years for that.”

Nadal was even cheering for England against Uruguay in the World Cup. “In the end we are Europe and England is a big traditional football [team],” he says, before taking congratulations from the former Wimbledon champion Pat Cash, passing through the Hurlingham locker room, for his French Open victory.

More than most, Nadal knows how precarious grass can be and he will take nothing for granted when he begins his quest for a third Wimbledon title against the talented Slovakian, Martin Klizan, on Tuesday. “The matches are so quick, decided on only a few balls,” Nadal says.

“I can lose in the first round for sure, that’s part of sport, but I am really trying hard because I really want to play well. But that’s sport and especially on this surface, it’s going to be a big challenge. The year I won, in 2010, I was two sets to one against, in my first two rounds.”

He adds: “Mentally I’m ready to compete, better than previous years, but we will see.”