Rafael Nadal, the former World No 1, is moving to a heavier-headed racquet this season in hopes of improving his serve. He acknowledges it could hurt his game in the short run. Karim Jaafar / Agence France-Presse

Rafa Nadal admits he is having to take risks to achieve the level required to win back the world No 1 ranking. The French Open champion is gambling with a heavier-headed racquet in the first tournament of the 2012 tour, even though he has had little more than a week to get used to the change.

Nadal is also taking a chance in coming to the Qatar Open while wrestling with doubts about his mental and physical state after an all-too-short break between seasons.

"I had to make the change even if I am not better in the beginning," he said of an equipment change he first considered making after losing the US Open final to Novak Djokovic in September.

"We had to make the decision so that it will be better in the future," Nadal said. "Probably that hurts my game a little bit to begin with. Is that a risk at the beginning of the season? Yes."

Nadal hopes the change will lend some extra weight to his serve, which at times has been the least potent of the world's top four.

His twin problems are that Djokovic last year took his game to a new level of intensity, and that he has been struggling with discomfort in his shoulder for several weeks.

Nadal also admitted a combination of this injury and continuing twinges in his knee, plus the shortness of the break between seasons, made him consider missing this week and going straight to Melbourne for the Australian Open.

He decided to delay the racquet change till now because of his commitments to the Tokyo and Shanghai tournaments, which were quickly followed by the ATP World Tour finals and the Davis Cup final at the start of December.

That left Nadal, after a short rest, with little more than a week to prepare for the 2012 season, increasing the risks in what he calls an "investment" in the weightier racquet.

"But it was still the right moment, to change," said the 25-year-old Spaniard. "If not now, then when?"

Nadal is a conspicuously resilient character, but still acknowledges this week will be "difficult" as he seeks a good preparation for the first Grand Slam of 2012.

Although he is a winner of 10 Grand Slam titles, Nadal has not won a tournament since the French at the start of June, and has lost his last six finals against Djokovic.

"I don't know if it's going to be enough to beat him now or to lose him 100 more times - I cannot predict that," Nadal said.

"What I can predict is I am going to work hard to try to be competitive enough to play with good chances against everybody, not only against him, because first thing, you have to be in the finals. That's a very difficult thing to do."

Nadal, the top seed, was set to begin the season on Tuesday against Philipp Kohlschreiber, the world No 43 from Germany, and has a possible semifinal with Gael Monfils of France.

If he wins that, he could have a final against his career-long rival, Roger Federer, the winner of a record 16 Grand Slam titles, who is seeking his fourth triumph in Qatar.