(CNN) -- "I'm not a machine, and like everybody I have better moments than others," Rafael Nadal told CNN in Shanghai.
After a year disrupted by injury, it was a moment of candor from the down-to-Earth 23-year-old, whose winning ways on the court had at times made him seem invincible.
"Tennis is a hard sport, a very, very tough mental sport because you play a lot of matches during the season and you have to be ready every week. So you need to be very focused all the time -- 100 percent physical and mental -- if you want to have chances to have a good result.
"Sometimes you feel you need to stop. I played every week for a long time and I forgot I had to stop for an injury."
Taking time out of the game earlier this summer to recover from tendonitis in his knees, Nadal missed out on defending his 2008 Wimbledon title, won in an epic final match against world number 1, Roger Federer.
Making his comeback just before the U.S. Open in August, he played into some form to reach the final of the Shanghai Masters tournament in October.
Even though he won five major tournaments in the first half of 2009, the lack of silverwear in the second half of 2009 isn't a worry. He retains his will to win and is happy that his job is something he loves.
"I never excepted be number two or Number one and have the chance to win Grand Slams. That's unbelievable for me, you know, I feel I'm a very lucky person because I work in tennis. My work is playing tennis and it's my hobby too, you know, so not everybody can work in one of his hobbies, so I feel lucky for that," he told CNN.
With six Grand Slam titles to his name already, the Majorcan believes he has a long future ahead of him in the game, despite his recent injury setback.
"I have seven years of my career right now and I am not finished, so I expect be here and hope be here for a long time."