since he crashed out of Wimbledon in the first round in June. He has twice finished the season as the top ranked player, more recently in 2010, and the first time in 2008, after he edged into the top position by winning gold at the 2008 Beijing Olympics.
The 27-year-old, tipped to eclipse Roger Federer's record of 17 Grand Slam titles, has won 10 ATP World Tour titles in 2013. Tennis legends Andre Agassi and Pete Sampras reportedly said Nadal could overtake Federer before he finishes his career.
Nadal believes he would need to sustain his form — and crucially his fitness — for the next four years if he is to better Federer's Grand Slam achievements. The current game is said by tennis pundits to be dominated by the 'Big Four' — Nadal, Federer, Djokovic and Briton Andy Murray.
However, Nadal is emerging as the dominant force and he has had the beating of Djokovic, coming out on top at both the French Open and US Open, as well as the Canada Masters. Djokovic has previously warned Nadal that he will not give up the top spot without a fight. "As long as there is a chance, I will fight for that top spot," he said ahead of the dual ATP and WTA event, which is being staged at Beijing's Olympic Park.
Roddick had Djokovic pinned up against a locker in 2008
Los Angeles: Retired American tennis player Andy Roddick has lifted the lid on his feud with world number one Novak Djokovic, revealing the two players almost came to blows in a locker room bust-up.
Roddick said he pinned Djokovic up against a locker in the US Open dressing room after Djokovic "beat the pants off him" at the final major championship of the ATP tennis season. Roddick, 31, did not say when the incident happened but the two had a very public row during the 2008 US Open. "I won't say his name, I'll just say it rhymes with 'Schmovak Schmokovic'," Roddick said on a panel discussion on the American sports network Fox.
"We got into it at the US Open