MADRID (AFP) - Rafael Nadal says his game this year has been too predictable and he has sometimes lacked drive on court -- weaknesses he plans to overcome for Wimbledon and the 2012 Olympics.

"With the years, you lose a bit of intensity. Intensity in your self-belief, concentration, being positive, believing things will go well -- those are in the mind. With the years you lose that a bit," he told the Spanish daily El Pais in an interview published Monday.

The 25-year-old world number two led Spain to a fifth Davis Cup title in December and won the French Open this year. But he lost in the Wimbledon and US Open finals to Novak Djokovic and surrendered his number one spot to the Serb as a result.

"My mind was good in the first half of the year, not perfect because I needed a bit more in the games against Djokovic. But it was fine," he told the paper. "I have started to work, fight again.. but clearly I lacked a bit in my level of tennis. When you have it, your mind responds better. I have needed to be less predictable playing. I have been too predictable many times during the season," Nadal said.

The Spaniard said he had a good 2011 overall but felt he was "bad" towards the end of the year and "very bad" when he crashed out of the season-ending ATP World Tour Finals to Jo-Wilfried Tsonga. "It was not a complete disaster but I did not win because I was too anxious," Nadal said.

"I tell myself: 'If I do a bit more I will be nearly back to winning anything again'. That is the motivation.”