Joaquin Rodriguez surged past rival Alberto Contador on the final climb to win the 12th stage of the 2012 Vuelta e Espana and extend his overall lead to thirteen seconds.

Rodriguez and Contador broke away from the peloton and rode wheel-to-wheel up the last stretch of a sharp ascent to finish the 190.5 kilometer stage.

"You can compare this end of stage to any in Italy, it is so explosive," Rodriguez commented after being celebrated on the podium. "People had explained it to me and even though people tend to exaggerate, I didn't expect it to be so difficult. I waited, then sprinted and won it."

Rodriguez, who had a 1-second lead on Contador entering the stage, won his second stage in 4 hours, 24 minutes, 32 seconds. Contador crossed 8 seconds later.

Christopher Froome of Britain finished fifth, 23 seconds behind to trail Rodriguez by 51 seconds overall. Alejandro Valverde dropped to 1:20 behind Rodriguez after finishing third ahead of Robert Gesink of the Netherlands.

Contador said he was unconcerned about losing 12 seconds to Rodriguez.

"I'm feeling good and when the mountain stages come, with longer finishes, then I should get even better," 2008 Vuelta champion Contador explained.

Tomorrow's stage 13 from Santiago de Compostela to Ferrol is the last before a pair of important weekend mountain stages that will further test Rodriguez's ability to hold off Contador.

"Alberto is going to really take it to us this weekend," Rodriguez explained. "The gap is very small and someone like Alberto makes you work very hard on a good day."

"I'm very happy to be in red jersey and to increase the gap size, but nothing is yet decided. The Vuelta is still long with very hard stages and everybody can have a bad day and falter, falling out of the fight for the general classification."

The 21-stage Vuelta a Espana ends in the Spanish capital Madrid on September 9.

Watch video highlights from all stages of the 2012 Vuelta a Espana in our videos section (U.S. only - due to geo broadcast rights restrictions).