Despite claiming that he's trying to shed 7.5kg of extra weight and wouldn't be a factor in the Tour de San Luis, Alberto Contador showed his class on the race's first mountaintop finish to take his first victory of 2012 and the race lead.

Contador reeled in the attack of home favourite Daniel Diaz (San Luis Somos Todos) along with Italian Vincenzo Nibali (Liquigas-Cannondale) in the finale of the 5km ascent of Mirador del Potrero, but was able to ride the pair off his wheel in the final kilometer.

”It was a perfect day for us with total control," said Saxo Bank director Philippe Mauduit. "Going towards the first climb we were in the first line and we put Jesus (Hernandez) in the breakaway in the climb and gained control of the pack on the descent and reeled in the escapees before launching Alberto (Contador) on the final ascent.

"He was superb. Naturally, he's not going to be in shape for the Tour just now but still he's the best. It was simply a great feeling watching him take off and take that first season win and we'll try to defend the leader's jersey."

American Levi Leipheimer (Omega Pharma-Lotto) answered Contador's challenge, however, and continued to surge through to the finish where the Spaniard prevailed in a two-up sprint. Colombian Miguel Angel Rubiano (Androni Giocattoli) completed the stage podium five seconds later in third place, followed by Stefan Schumacher (Christina Watches) in fourth and Diaz, who hung on for fifth at 12 seconds.

"Alberto's got more punch than me and I think when it comes down to it he knows how to sprint better than I do and he showed that here today," Leipheimer told Cyclingnews. "I felt really good. My team worked really hard before the last climb, and I think that that helped, but it was really windy. There was a lot of headwind and sections where we went into the mountain and there was a tailwind and no wind and I tried to attack every time there but it was very short-lived.

"I'd come into the headwind and let off the gas. I had a feeling that everyone was just hanging on but there's not a lot you can do about that."

Leipheimer was the only rider to answer Contador's winning attack, and the Omega Pharma-Quick Step rider was quick to continue pushing the pace to the finish line.

"When Alberto put in his last attack and I was the only one with him. I pulled a lot because tomorrow's a time trial and if you gain seconds over people it means a lot," said Leipheimer. "I had the feeling that Alberto was on the limit, but it was just a choice I made and I think it was a good one."

With the winner's time bonus, Contador now leads Leipheimer by four seconds on general classification with Stefan Schumacher third at 19 seconds. Tomorrow the Tour de San Luis peloton faces an out-and-back 19.5km individual time trial in the city of San Luis on a course with a gentle rise and descent.

"Alberto and I are pretty close in the time trial but I've been able to beat him a lot in the past so hopefully tomorrow I can do it," said Leipheimer.

Double dose of category one climbs loom

The first course of action following the start in the picturesque, sylvan setting of Estrancia Grande was to attend to a rash of mechanicals suffered by riders such as sprint leader Emmanuel Guevara (San Luis Somos Todos), Luis Mansilla (Chile), Jimmy Casper (Ag2R) and Juan Jose Haedo (Saxo Bank).

Soon afterwards two riders, Tomas Metcalfe (Carmin-Prio) and Gregory Duarte (Uruguay), went out on the attack in advance of the day's first KOM, the category 3 La Florida ascent at 26km, a mere prelude to the two category one climbs to come.

Renato Dos Santos (Brazil) left the confines of the peloton in a solo chase and at the base of the La Florida ascent trailed Metcalfe and Duarte by 40 seconds while the field was 2:30 in arrears.

Metcalfe crossed the La Florida summit first, followed by Duarte and Dos Santos, and the now three-strong break had extended its advantage over the peloton to 3:40

With the monster Alto de Nogoli summit looming at 60km, the peloton was momentarily keeping its powder dry and the three leaders continued to stretch their lead to over six minutes as they began the 25.5km ascent.

When the escapees extended their advantage to 8:00 minutes pressure began to be applied in the peloton, resulting in a decimated field.

By the time the three leaders closed to within 4km of the summit an elite selection of approximately 20 riders had emerged as the first chase group, only three minutes back, and included Jesus Hernandez (Saxo Bank), Cayetano Sarmiento (Liquigas-Cannondale), French champion Sylvain Chavanel (Omega Pharma-Quick Step), Sergio Godoy, Alvaro Argiro and Eduardo Sepulveda (Argentina), Miguel Rubiano (Androni Giocattoli) Stiver Ortiz and Mauricio Ardila (Colombia-Comcel), Magno Nazaret (Funvic), David Livramento (Carmin-Prio) and Karol Domagalski (Caja Rural).

Dos Santos crested the Alto de Nogoli climb first, followed by Rubiano and Duarte.

Plenty of riders took risks on the descent off of Alto de Nogoli and fueled by a Saxo Bank-led chase a general regrouping of approximately 60 riders formed at the head of affairs after passing through the first intermediate sprint, claimed by Jorge Giacinti (San Luis Somos Todos).

Angelo Pagani (Colnago-CSF Inox) took advantage of a lull in the action, and launched a solo attack from the front group in the flat prelude to the summit finale.

With approximately 50km to the finish atop the Mirador del Potrero, the Italian's lead stood at 1:45 to the first chase group, with the second chase group 4:25 in arrears.

Closing in on the day's second intermediate sprint a crash occurred in the first chase group with Maximiliano Richeze (Argentina) and recent Vuelta Chile champion Patricio Almonacid hitting the asphalt. Richeze chased back to the group, but sought treatment from the race doctor, while Almonacid abandoned.

Meanwhile, solo leader Pagani suffered his own bad luck as he flatted, hastening the juncture by the 60-strong chase group inside of 18km to go, and the catch was made in advance of the final intermediate sprint, taken by Edvin Avila (Colombia).

With just 11.5km until the finishing ascent, the teams of the general classification contenders came to the fore to set up their team leaders for the showdown on the Mirador del Potrero.

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