Wimbledon, England:Defending champion Rafael Nadal withdrew from Wimbledon on Friday after losing his battle to fully recover from a knee injury in time for the third Grand Slam of the year which starts on Monday.
"To not play Wimbledon is one of the toughest decisions of my career," said the Spaniard at a hastily-arranged news conference at the All England Club.
"I have some time now to recover and will work very hard to return as soon as possible."
Nadal, the world number one, was forced to miss Queen's last week as a result of the problem, but the Spaniard flew to London this week after intense rehabilitation in Barcelona in a desperate bid prove his fitness for Wimbledon.
The Spaniard, winner of a thrilling five-set final against Roger Federer at Wimbledon last year, hoped that he would perform well enough in two exhibition matches at London's Hurlingham Club on Thursday and Friday to give him hope he could defend his crown.
But he struggled badly in Thursday's defeat against Lleyton Hewitt and, although he moved around court a litte better, he suffered another loss to Switzerland's Stanislas Wawrinka 24 hours later.
The 23-year-old has been bothered by the tendinitis problem for several years, a legacy of his all-action style and his devotion to clay courts.
He was well below his best at the French Open where he suffered his first defeat, crashing out in the fourth round to Robin Soderling, and has finally decided to rest rather than risk further long-term damage.
Nadal is the first champion not to defend his Wimbledon title since Goran Ivanisevic, who retired in 2002, a year after beating Patrick Rafter.
John Newcombe and Stan Smith also didn't defend the title in the modern era.
The reigning Australian Open champion will now concentrate on recovering from the injury in time to play in the US Open, which starts in late-August.
With Nadal sidelined, Federer, who succeeded the Spaniard as French Open champion, will be a clear favourite to regain the Wimbledon title he won for the fifth time in 2007.
Federer will become the number one seed, while Britain's Andy Murray moves from the third spot to second seed.
Nadal, who has tendinitis and fluid on his kneecaps, had been handed a first round tie against France's Arnaud Clement in Friday's draw, with a potential second round clash against Hewitt and a potential semi-final showdown with world number three Murray.
Argentina's Juan Martin del Potro, the fifth seed, moves into the slot in the draw vacated by Nadal.
Del Potro's place will be taken by the number 17 seed, David Ferrer. The 33rd player on the men's list will slide into Ferrer's position and a lucky loser from qualifying will fill the final slot.