Schleck, Menchov faves

"I think a straight duel between Menchov and Andy Schleck is more than likely," Guillen told Reuters. "Menchov is a very experienced rider in the Tour of Spain, whilst this year's mountainous route will suit Andy down to the ground.

"But we shouldn't forget Andy's brother, Frank, because I've heard he is in great form, or (2008 Tour de France winner) Carlos Sastre."

Andy Schleck has twice finished second in the Tour de France, in 2009 and 2010, while Menchov, third in Paris this year, won the Tour of Spain in 2005 and 2007.

Guillen said he was not discouraged by last year's withdrawals by both Schleck brothers before the halfway point.

"Both riders quit for physical reasons, not because they wanted to. I know they're both really motivated this year."

Spain's top stage racer Alberto Contador, who won his country's biggest race in 2008 is not taking part but Guillen said the level of participation was high enough for the three-times Tour de France champion not to be missed.

"If Alberto had come it would have been the icing on a very large cake. I think this year the level of participation is the best the race has seen in years."

Guillen said he expected high-level sprint finishes, in part thanks to the first-time participation of Briton Mark Cavendish.

"Cavendish is the fastest rider in the world but there are many others like Oscar Freire (of Spain) and Thor Hushovd (of Norway) who will be trying to beat him. Mark isn't going to have it easy."

Time bonuses of 20, 12 and eight seconds for the top three riders will give the fast men the chance to claim the leader's jersey, which has changed in colour this year from gold to dark red.

"As everybody knows after Spain's sporting success this year, red is the colour of sport in our country and as such will help give the race its own identity," Guillen said.

Summit stage finishes in Andorra and by the Lakes of Covadonga, home to some of the last wolves in western Europe, are expected to have a big effect on the overall classification, with the first leader being decided by a night-time team time trial in Seville.

"Holding the first stage at 10 p.m. at night is something different and spectacular," said Guillen.

"We had a great start in Holland last year and ideally this year's first stage will be equally memorable."