METZ, France -- Peter Sagan of Slovakia claimed a third stage win by edging Andre Greipel of Germany in a sprint finish on Friday, escaping another day that involved a huge pileup.
Fabian Cancellara of Switzerland retained the yellow jersey for a seventh day after the 129-mile sixth stage from Epernay to Metz through the Champagne region.
Giro d'Italia champion Ryder Hesjedal of Canada, Frank Schleck of Luxembourg and Mark Cavendish of Britain were among the riders involved in a huge crash that split the peloton 16 miles from the finish.
The crash left riders and bikes all over the road but main contenders Bradley Wiggins and defending champion Cadel Evans escaped unscathed.
The peloton, led by sprint teams from Orica-GreenEdge and Lotto-Belisol, then caught four breakaway riders with just over a mile to go.
"I don't know how many stages I can win," Sagan said. "Three is already good, maybe more."
Greipel, hoping to claim a third consecutive stage win, was the first to make his move in the final section but couldn't resist Sagan's surge.
"I was in a good position, I kept it and then nothing hampered my effort," Sagan said. "I took Greipel's wheel and everything went according to plan."
Competing in his maiden Tour, Sagan was involved in a crash on Thursday but recovered quickly.
As spirited fans cheered the riders by lifting glasses and Champagne bottles on the side of the road, American rider David Zabriskie launched an attack just 3 miles after the start. He was joined by Davide Malacarne of Italy, Romain Zingle of Belgium and Karsten Kroon of the Netherlands.
The four breakaway riders collaborated well and built a four-minute lead over the peloton before Cancellara's teammates moved to the front of the bunch to set up a faster tempo.
But a crash involving about 20 riders after 21 miles upset the chase and the escapee's advantage grew to more than six minutes after 26 miles.
Those in the crash included Rabobank team leader Robert Gesink, winner of the Tour of California this year, and former Spanish Vuelta champion Alejandro Valverde of Spain. But all the riders involved in the pileup were able to get back on their bikes.
Another crash slowed down the peloton with 37 miles to go, with Greipel hitting the ground.
As far as title hopes go, the biggest casualty of the last pileup was Hesjedal. He had entered the stage in ninth place, 18 seconds back, but straggled across the finish with an injured more than 13 minutes behind -- all but ending any reasonable hopes of Tour victory for him.
"It was the scariest crash I've ever been in, we were doing like (43 mph)," said Garmin teammate David Millar, who had black chain-grease marks all over his arm. "God knows how it happened, some idiot ."
The race moves into the mountains on Saturday with a 123-mile ride to the ski resort of La Planche des Belles Filles in the Vosges. The stage features the Tour's first category-one climb, a tough 3-mile ascent with the final few miles at an average gradient of 14 percent.