Rafael Nadal is looking for his first ATP World Tour Finals title. (Clive Brunskill/Getty Images)
LONDON -- Rafael Nadal, who is making his sixth appearance at the ATP World Tour Finals, has yet to win the season-ending tournament, which he has contested each time on his least favorite surface, indoor hard courts. Nadal said he would love to see the tournament change surfaces every year. After a two-year run on outdoor hard courts in Houston from 2003-04, the World Tour Finals spent four years on indoor carpet/hard courts in Shanghai and the last four years and counting on indoor hard courts in London.
Asked Monday why he struggles at the round-robin event featuring the eight best players for the year, Nadal said: "One of the small reasons was fatigue. One of the big reasons is I have not always been a fantastic player on indoor. Just a few times have I been able to play at a high level on indoor.
"The third thing is because I feel like I am unlucky," Nadal said of the surface of choice. "During these nine years the Masters Cup was on indoor, a surface that was not the best for me. So probably for me I was a little bit unlucky in this because in the past we had the Masters Cup on other surfaces. I understand, but I think this is unfair."
The World Tour Finals, which used to be called the Tennis Masters Cup, will remain here until at least 2015 and there's already talk of extending the arrangement beyond that. Nadal made it clear that his critique wasn't aimed at organizers.
"I cannot find a better place to have a Masters Cup than here because the stadium is one of the best stadiums I've ever played," he said of the O2 Arena in London. "But that doesn't mean the ATP cannot be a little bit more fair to all the players. In the World Tour Finals, we qualify on all surfaces. It would be a little bit great -- I'm not talking about me because I know it won't happen for my generation, so I'm talking for the next generations -- [to have] something more fair to the players and I think for the fans it would be something more interesting to change the surface every year."
Novak Djokovic would like to see the event moved around more often -- no more than three years in any one city -- but for different reasons.
"Because of the promotion of tennis," Djokovic said at his pre-tournament news conference. "Just having the popularization of this sport in places where tennis isn't as popular. I think that if we are looking forward to expand the success and the consciousness of our sport, which is very global, then we should look into that. We should look into allowing other cities in the world compete for this tournament."
Nadal needs only two victories at this week's World Tour Finals to clinch the year-end No. 1 ranking over Djokovic, who arrived Sunday night after winning the Paris Masters and improving to 17-0 since the U.S. Open. The Spaniard said the No. 1 ranking meant more to him when he earned it for the first time, in 2008, but now he's just pleased he's been able to play healthy and at a high level since returning from a seven-month absence in February.
"For me, the history of this year is not No. 1," he said. "The history of this year, my year, is after seven months without any chance to compete, without the chance to play or practice tennis, I was able to be back and win from the beginning."
Nadal opens against David Ferrer during the day session Tuesday. Djokovic plays Roger Federer in the evening.
UPDATE: Federer disagrees with Nadal about changing surfaces.