Mads Pedersen became the third Dane to win a stage on this year's Tour de France when an escape group beat the peloton to Saint-Etienne on a baking-hot dash across the Rhone Valley on Friday as riders braced to face temperatures of up to 40 degrees this weekend.

His countryman Jonas Vingegaard retained the overall lead, which he claimed by winning stage 11, while Magnus Cort Nielsen won stage 10 in a Tour de France that had started with three days in Denmark.

A bunch sprint had been expected on this 193km stage 13 run from the foot of the Alps, but as the heavier built riders, who dominate the sprints, began to struggle in the searing temperatures, a seven-rider break began to dream of a stage win.

Australian sprinter Caleb Ewan fell when he appeared to lose focus and braked hard into a corner, tumbling alone near the head of the peloton.

Quick-Step sprinter Fabio Jakobsen also was dropped as the pack chased the escape, and with no collective will to reel in the escape, the peloton then gave up the game 25km from Saint-Etienne.

Pedersen clearly is a man for the extremes, as he won the 2019 world championship road race in freezing Yorkshire rain.

On Friday, he dealt with a heatwave with the same elan, whipping his rivals Hugo Houle and Fred Wright in the home straight.

"It was a bit of a gamble," the 26-year-old Pedersen said after his first ever Grand Tour win.

"I had a couple of good days in the mountains, my legs felt good, so when it came to the sprint I had enough."

Great To Be A Dane

Vingegaard, Tadej Pogacar and Geraint Thomas, the top three in the overall standings, all cruised over the line together.

"It's great to be a Dane right now, a third win for Denmark is incredible," Vingegaard said.

Pedersen said the Danish success was down to grass roots investment in a country where five times more journeys are made by bike than by car.

"All the good work from local and continental teams and investment in Danish cycling is paying off," he said.

Much has been made of how Jumbo riders have been wearing cooling jackets ahead of the stages as the heatwave builds up.

They are the only team using such jackets.

"Regular cold drinks and ice packs on the back as often as you can during the race to keep the body temperature down, that's what you do," said Vingegaard.

"I wouldn't say the heat was a problem," said the man who was cheered round the streets of Copenhagen by tens of thousands of rain-poncho wearing spectators two weeks ago.

The heatwave in France will continue to build over the next couple of days with temperatures expected to edge towards 40 degrees.

Saturday's stage 14 is a 193km race from Saint-Etienne to Mende over hills preceding a flat run from Rodez to Carcassonne as the heat hits its peak Sunday.