Nadal looking for success

The 20-year-old Spaniard came from two sets down to beat Croatia's Ivan Ljubicic in a five-set thriller at the Madrid Arena last year but Federer did not play in the tournament.

The Swiss missed out because of a foot injury and will be anxious to continue a sensational season with a triumph at one of only four Master Series titles to elude him.

The 25-year-old's best result in Madrid was reaching the semi-finals in 2003, where he lost to eventual winner Juan Carlos Ferrero.

Such is the domination of the world's top two players that they have won 13 of the 16 Masters Series events in the last two years.

Although Federer is still streets ahead of Nadal in overall tournament victories, adding three more grand slams to his haul this season, the Spaniard has beaten him in four of their five meetings this year.

But the big two will not have it all their own way as every one of the world's top 10 players will be in Madrid as well as past winners Ferrero and Marat Safin, Gaston Gaudio and British pair Tim Henman and Andrew Murray.

Last year's losing finalist Ljubicic, in-form James Blake, unpredictable Marcos Baghdatis and Russia's Nikolay Davydenko should all provide stiff resistance as they compete for points to secure places in the end-of-season Masters Cup in Shanghai.

"Obviously I would love to retain the title in Madrid," Nadal was quoted as saying in Spanish sports daily AS on Saturday.

"But this time all the world's best will be here and the surface isn't my favourite.

"For me this is simply one of the best tournaments in the world. Last year I'd practically lost the final and the support of the fans helped me turn the match around. That is an experience I will never forget.

"From the perspective of the fans the presence of Federer will make the event even more spectacular."

As well as the now traditional models as ball girls, the Madrid tournament will also feature the "hawk-eye" officiating technology that allows players to challenge and review calls.

Each player will be allowed two challenges per set plus an additional one in the event of a tiebreaker. If the player is correct he retains his challenges, if not one of them is lost.

The system has been used successfully at three Masters Series events in North America as well as the U.S. Open and six other ATP events.