After two weeks and five leaders, the Vuelta is still very much up in the air. Roberto Heras has thePICTURE BY LAVUELTA.COM Yet again the Tour of Spain has lived up to its reputation for producing the most unpredictable and exciting action seen in any major stage race during the entire season. With just six stages remaining starting with Tuesday's flat run to Caceres, defending champion Roberto Heras leads Alejandro Valverde by just five seconds, with third-placed Santi Perez at 1-45 after winning both of this last weekend's stages. All three Spanish riders have reason to believe that they will be the one who prevails in Madrid next Sunday. Heras admits that yesterday's mountain time trial on the Sierra Nevada climb above Granada did not go anywhere near as well as he'd hoped, but believes he should thrive in the next few days when the race takes place on roads he knows well. "The race is much more open now," the Liberty Seguros leader told AS. "I believe that the three riders who are in the top three places now ought to fill the podium spots in Madrid, but it remains to be seen in which order." Heras should gain inspiration in Wednesday's stage to the Covatilla ski resort above his home town of Bejar. "We'll be on my territory there and I'm sure the finish will be thrilling," said Heras, who also explained that his bike change early on in the Sierra Nevada TT was due to a puncture. His second bike was, he said, set up exactly the same as the first. Valverde admitted he thought he would end Sunday's time trial in the leader's gold jersey, but then lost some momentum in the last couple of kilometres. "The important thing was that I got time back on Heras and came out of the stage feeling revitalised," said the 24-year-old CV-Kelme rider. "I've got a lot of respect for Heras, who is the best climber in the world, and of course I will be taking Perez into account as well. He is in superb form. From a personal point of view, fortunately I now seem to have recovered from my fall last week. My knee is still a bit inflamed, but it's not too bad." Perez is still painting himself as the total outsider who is simply pleased to be competing with the likes of Heras and Valverde, but his form over the weekend suggested he is reaching his best at just the right moment. After Saturday's emotional stage win, Perez found it difficult to sleep before the time trial, but felt good on the morning, when he went out for a pre-stage warm-up with team-mate and local resident Oscar Sevilla. Erstwhile Phonak team leader Sevilla, who announced last week that he has signed a deal with T-Mobile for the next two seasons, both advised Perez on how to tackle the Sierra Nevada and tried to motivate his team-mate, evidently to very good effect. Heras may be the best climber in the sport, but at the moment he does not look to have the matching of Perez in this race. "It will be a success for me if I finish on the podium," said the 27-year-old from Asturias in the north of Spain. "I can't allow the euphoria of the last couple of days to let me get carried away. If I can maintain this level of form I will try to win on the Covatilla and Navacerrada."