RAFAEL Nadal believes the tough times he endured in 2009 paved the way for his phenomenal success this season.

The world number one ended the year by reaching the final of the Barclays ATP World Tour Finals for the first time at London’s O2 Arena on Sunday and, although he came up short against Roger Federer, he demonstrated he will once again be the player to beat in 2011.

When Nadal won the Monte Carlo Masters in April it was his first title in almost 12 months. One of the lowest points in that period, where he was troubled by injury and loss of form and confidence, came at the end-of-season showpiece in London last year.

The Spaniard lost six successive sets and ended the week with many people questioning whether he could ever climb back to his former heights. The answer was an emphatic yes.

Nadal completed a clean sweep on clay, culminating in his fifth French Open title, and he then made it three grand slam victories in a row by winning Wimbledon and the US Open – making him the youngest man to complete a career Grand Slam.

Looking back on 2010, the 24-year-old said: “It was difficult at the beginning but, after a tough time, probably because I had this difficult time, I was able to play with ambition all season.

“All the time I was trying to keep winning and keep playing well because when you spend 11 months without a victory, you really know how difficult it is to win tournaments.”