Former world No. 1 Rafael Nadal said that it is not fair for players like him to play the ATP World Tour Finals on hard court.

The 29-year-old told the Daily Mail: "I am not sure if it is 100 per cent fair that we qualify for the World Tour Finals playing on grass, hard, clay and indoors, and since 2005, when I qualified [for the first time], it is already 11 years that every single time [it has been] on indoor hard.

"I believe that it's not fair that a player like me really never played on a surface that was a little bit more favourable. I always played on the worst surface possible for me.

"If it's indoor at the 02, then great, but you can build a different type of surface there. It is a fantastic place to organise a World Tour Finals. The atmosphere is just amazing and I am very happy it is there. I enjoy it every time I have had the chance to be there, but we can play on clay there too."

The 14-time Grand Slam champion failed to win a major titile for the first time since 2004. The most bitter of blows came at Roland Garros in June when his reign on the Parisian clay came to an end at the hands of Novak Djokovic in the quarterfinals.

Nadal said he has found his form before the ATP World Tour Finals to kick off at the O2 Arena on Sunday after reaching finals in Beijing and Basle.

"It is a different feeling [this year]. I had a lot of problems during the whole second part of the season last year. It was a good first part but then I broke my wrist and I had appendicitis. It was so tough.

"In general, I feel that is past. I was able to improve during the whole season, especially the last couple of months. I've felt that I am playing better and better, I feel that I am enjoying it again, the fact that I am playing my style and I am able to play a little bit more aggressive game because I am in control of my emotions."