Peter Sagan wins 7th stage of Tour de France

• Sagan held off challenge from John Degenkolb to clinch his first stage victory in this year's Tour
• Daryl Impey kept the overall race lead
• Sagan extend his lead in the contest for the sprinters' green jersey

LBI, France (AP) — Slovakian rider Peter Sagan won the hilly seventh stage of the Tour de France in a sprint finish on Friday, and Daryl Impey kept the overall race lead.

Sagan held off a challenge from John Degenkolb of Germany to clinch his first stage victory in this year's Tour and extend his lead in the contest for the sprinters' green jersey. Italian sprinter Daniele Bennati was third.

Impey began the day as the first South African rider to wear the yellow jersey, but he will likely relinquish it after Saturday's first of two difficult days of climbing in the high mountains of the Pyrenees.

Keen to get Sagan in a good position to attack, the Cannondale team increased the pace considerably near the end. Three of them almost fell near the end as they mistimed a corner and their bikes wobbled, but their expert handling and reflexes rescued them.

Sagan's stage win moves him 94 points clear of German Andre Greipel and he is already more than 100 points ahead of his archrival Mark Cavendish — the 2011 green jersey winner — who was left behind and could not even challenge for the stage win.

The average speed picked up considerably in the fourth hour, jumping up to nearly 50 kilometers per hour (30 mph) in temperatures again well into the thirties Celsius (above 90 Fahrenheit) for the 205.5-kilometer (128-mile) hilly leg from Montpellier to Albi.

In fact, there has hardly been a drop of rain so far — perhaps unsurprising given that the race started on the picturesque island of Corsica before jumping over to Nice on the French riviera, and then down to Marseille and Montpellier.

With 40 kilometers remaining, the front three of Belgian rider Jan Bakelants, Frenchman Cyril Gautier and Spaniard Juan Jose Oroz led the yellow jersey group surrounding Impey by 45 seconds and then by 20 with 10 kilometers left.

Veteran American rider Christian Vande Velde pulled out after being caught up in an early crash — one of several that have marred a nervy start to the 100th edition of the showcase race.

Norwegian sprinter Edvald Boasson Hagen, Colombian rider Nairo Quintana and Michael Schar of Switzerland were among those to also fall about 111 kilometers into the stage.

They rejoined the race, but the 37-year-old Vande Velde — who hurt his back in a crash earlier in the race — was unable to continue.

It is the third time the American has failed to finish the Tour.

In 2001, Vande Velde crashed out during a wet team time trial stage and three years ago he had to abandon after falling in a mass pile-up on stage three.

"The multiple contusions and abrasions he suffered in today's crash, compounded with the injuries he sustained on Stage 5 which included a blood clot in his neck muscle, a loosened screw in his clavicle plate and upper back injuries, made it impossible for him to finish today's stage," Garmin's team doctor Prentice Steffen said.

There have been several multi-rider crashes in what has been a nervy Tour so far.

On the first stage, there was a big crash close to the end after Tour organizers caused anxiety in the peloton by changing the designated finish line because a team bus was stuck on the line, before changing their minds again moments later.

The fifth stage featured two separate crashes, the second right on the finish line, and the sixth stage claimed British sprinter Mark Cavendish among the fallen.

Early into stage 7, German veteran Jens Voigt, who is riding in his 16th Tour, and Frenchman Blel Kadri were part of six riders who broke away soon after the start, but four of them were caught to leave only the 41-year-old Voigt and Kadri alone in front.

But any dreams Voigt had of becoming the oldest stage winner since Pino Cerami in 1963 ended when he was caught with about 100 kilometers to go.

Riders faced a tough weekend in the Pyrenees, where race favorites like Chris Froome and Alberto Contador are likely to attack on Saturday's climb up the famed Col de Pailheres, which winds upward for 15 tortuous kilometers at a gradient of eight percent.