CASTIGLIONE DELLA PESCAIA, Italy -- Overall leader Alberto Contador injured his arm in a crash on the final sprint of the sixth stage of the Giro d'Italia on Thursday.

Contador was able to get up and finish the stage but was unable to lift his left arm on the podium to put on the pink jersey, and did not pick up the celebratory bottle of champagne -- a sharp contrast to the previous day when he sprayed it cheerfully around after claiming the overall lead.

The Spaniard, who is attempting to become the first rider since Marco Pantani in 1998 to win the Giro and the Tour de France in the same year, will undergo tests and X-rays, his Tinkoff-Saxo team said.

"It's a serious blow, we have to evaluate his condition," Tinkoff general manager Stefano Feltrin said.

Contador's press officer was more optimistic.

"He's hurt himself on the knee and he's got a bad shoulder as you can see, but he should be OK to continue," Jacinto Vidarte said.

The crash occurred in the final 300 metres as Daniele Colli hit the camera lens of a spectator leaning over the barrier and went down, bringing half the peloton down with him. Colli was immediately taken to a hospital and his team confirmed he broke his arm.

Contador and the other riders involved did not lose any time as it happened in the final three kilometres. He maintained a two-second lead over Italian title hopeful Fabio Aru, and a 20-second advantage over third-place Richie Porte.

Andre Greipel won the bunch sprint at the end of the 183-kilometre leg from Montecatini Terme to Castiglione Della Pescaia. The German was perfectly led out by Lotto Souda teammate Greg Henderson, and he had enough power to beat Matteo Pelucchi by a bike length.

Sacha Modolo was third.

"We (the team) have been working so long together and we are friends, which makes it easier to fight for each other and for the victories," said Greipel, who finished third in the second stage after opening his sprint too early. "Everyone went for it today and deserved victory.

"The whole team did a great job from kilometre zero, and the last 3K went how we planned it on the bus this morning. Today, I didn't make the mistake to go too early, and I'm happy we finished it off with victory."

Friday's seventh stage is the longest of the race, a mainly flat 264-kilometre leg from Grosseto to Fiuggi.

The 98th Giro ends May 31 in Milan.