The 24-year-old Spaniard, who has won the last three majors, could become only the third man to hold all four slams at the same time if he can win the Australian Open in January.
Nadal is looking to claim a record 19th Masters title in Shanghai this week but has played down the likelihood of achieving a clean sweep in 2011.
“I hope to have the chances to win four titles next year,” Nadal said. “But for me, that is impossible. I will try to keep playing well, but the Grand Slam is not the case. That’s for sure impossible, I think.
“Last year and the beginning of this was difficult and hard for me. So maybe for that reason I was able to push hard in all the tournaments, play with 100% motivation and try 100% in every moment.”
The nine-time grand slam champion added: “If you are winning, you want to keep winning because you never know when this is going to stop.
“So you have to do your best. When you are healthy, you have to enjoy the moments when you can because, the difficult moments are going to come back.”
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BIOGRAPHY: Ethan Hazard
BIOGRAPHY: Daniel Sturridge