Joaquin Rodriguez withstood Alberto Contador's repeated attacks to successfully defend his overall lead in the 2012 Vuelta a Espana's 15th stage - a stage won by Antonio Piedra of Caja Rural.

Rodriguez stayed close to Contador's back wheel with every surge by his fellow Spaniard on the last hors categorie climb to the finish line at the Lagos de Covadonga summit.

"Thank God there weren't any more kilometers to go because, if so, I wouldn't have made it," an exhausted Rodriguez said after crossing the finish line in the thin mountain air. "Fortunately, I had that little burst for the final 500 meters."

Despite protecting his lead by finishing in the same group as Saxo Bank - Tinkoff Bank's Contador, Rodriguez said the former Vuelta a Espana winner was in fine form.

"(Contador) is all over me. He is in charge," Rodriguez explained. "His attacks are top rate. I was amazed at his speed on the climb."

Piedra separated from a small breakaway group with just over 10 kilometers to go and finished the 116-mile stage in the Picos de Europa mountains in 5 hours, 1 minute, 23 seconds.

Ruben Perez of Euskadi-Euskaltel, Lloyd Mondory of Ag2r La Mondiale and Piedra's teammate David de la Fuente were next, just over two minutes behind the pacesetter.

Rodriguez, Contador and Movistar's Alejandro Valverde finished together 9:25 behind.

Rodriguez maintained his 22-second lead over Contador, and Valverde moved third in the overall classification at 1:41 back.

"I am not worried about Rodriguez who is riding stronger than ever," Contador claimed after being unable to escape from Rodriguez' strong grip in today's stage. "He is stronger than ever, but I am not going to win anything by not trying. You never know when a rider will have a bad day. You can rest assured I will fight until the last meter."

"I may not be as strong as I could be because of my long break from racing, but I simply enjoy being here after too long a period away from racing. It's amazing to feel the love and support from the crowd every day. Tomorrow the goal is simple. I have to attack and keep attacking so I hope to recover and be stronger than today," Contador continued.

The biggest loser of the day was Christopher Froome of Team Sky Procycling.

The British rider could not stay with the other contenders and saw the gap between him and the red jersey grow to 2:16.

"It was a really tough climb today, I am really suffering," said Froome, runner-up both at this year's Tour de France and last year's Vuelta a Espana.

"I am just trying to do as much as I can every day," he explained while realizing that his chances of winning the Spanish classic are dwindling. "I am not sure where I am going to end up. I'll just do the maximum possible and I am happy with that."

Tomorrow, riders face a third straight mountain stage that is arguably the most demanding of this year's Vuelta and thus its queen stage. The 183.5 kilometer stage starting from the city of Gijon takes riders through four category climbs and finishes at the Cuitunigru summit.

The 21-stage, three-week Vuelta a Espana finishes in 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).