SAGUNT, Spain (AP) Chris Froome maintained his lead of the Spanish Vuelta after Tejay van Garderen crashed twice during the sixth stage on Thursday.
Van Garderen entered the stage in second place at 10 seconds behind Froome. But the American slipped to fourth place and :30 seconds back after his error-prone day.
Esteban Chaves relieved Van Garderen as Froome's closest chaser at :11 behind, followed by Nicolas Roche at :13 back.
Poland's Tomasz Marczynski claimed the stage after beating two other breakaway riders to the finish line of the 204-kilometer (127-mile) run from Vila-real to Sagunt that included four category-three and one category-two climbs.
It was the Loto Soudal rider's first win at a grand tour.
''It's an incredible emotion. I came here really wanting to fight for a stage,'' Marczynski said. ''I believed that I would do it and today was the day.''
After a large breakaway group set off, the long stage became a frantic chase when Alberto Contador attacked the top riders on the final ascent over the Puerto del Garbi summit.
Froome was the only title rival able to keep up, leaving the rest to play catch up.
Contador, a three-time champion who will retire after his home race, said he knew the terrain was the perfect place to strike.
''I planned the attack. I thought it was a good day to get rid of some riders,'' said Contador, who remained more than three minutes behind.
Van Garderen crashed shortly after on that ascent. He then went down again going through a roundabout.
Chaves, Roche, Fabio Aru and Vincenzo Nibali all managed to make up the distance in the descent to the finish line.
Friday's stage is a hilly 207-kilometer (128-miles) ride from Lliria to Cuenca.
The three-week race ends in Madrid on Sept. 10.