Spain's Samuel Sanchez won the first Olympic cycling gold medal event on Saturday, beating out Italy's [Images] Davide Rebellin after a grueling 245-km road race from the Forbidden City in ancient Beijing [Images] to the Great Wall.

Fabian Cancellara of Switzerland [Images] took the bronze after the three sprinted on the final uphill portion of the course to make it to the podium.

Sanchez and Rebellin, who celebrated his 37th birthday with a silver medal, were part of a lead group in the final kilometers and Cancellara launched an attack to escape the peloton and join the leaders for the final sprint.

The road race was the first endurance sport of the Olympics [Images] that tested Beijing's notorious pollution, heat and humidity. Dozens of cyclists who dropped out of the race -- including one of the favorites, German Stefan Schumacher -- said the elements and pollution made the tough course even harder.

Spain's Alejandro Valverde was the pre-race favorite but the Spanish riders had said they would work for whichever cyclist felt the best during the race.

"The important thing is for Spain to have won gold," said Spain's Carlos Sastre, this year's Tour de France [Images] winner.

"It was a controlled race from us. At first we were working for Alejandro but in the end it turned out Samuel felt the best and so we played his card."

Defending Olympic champion Paolo Bettini, another favourite, said he had also expected Valverde to be the man to watch.

"In the finale, it was a Spanish-Italian fight," Bettini said. "I was watching Valverde and Davide was watching Samuel. I picked the wrong guy."

The heat and humidity took its toll. Schumacher, also a favorite for Wednesday's time-trial, left on the fifth of the seven 24-km laps on the hilly circuit between two sections of the Great Wall of China.

"It's very, very hard with the heat and the humidity," Schumacher said after leaving the course.

"I have a very, very strong headache. I suppose it's the pollution. "Obviously I'm extremely disappointed."