'Unfortunately this year I won't be able to play at Wimbledon,' he told a news conference.

The Spaniard, who has been struggling with tendonitis in his knees since being knocked out of the French Open last month, tested his fitness in two exhibition matches this week.

After losing both matches he decided not to defend his Wimbledon title, just three days before the start of the major.

Nadal will be the first man not to defend his All England Club crown since Croatia's Goran Ivanisevic skipped the grasscourt grand slam in 2002.

'Not to play Wimbledon is one of the toughest decisions in my career but the decision was made easier because I don't feel ready to compete at 100 per cent,' said Nadal, who becomes only the third man unable to defend his title at the championships.

'I don't feel like I'm ready to play in a tournament that is as important as Wimbledon.'

'I tried everything, I tried hard in the last week to get in the best condition and today was my last test,' added the world number one, who tried to play through the pain in an exhibition match against Stanislas Wawrinka at the Hurlingham Club on Friday.

'I didn't feel terrible but I was not at my best.' -- REUTERS