Belgian Maxim Van Gils won the mountainous sixth stage of the Tour Auvergne-Rhone-Alpes on Friday as his Australian teammate Luke Tuckwell finished third and took the leader's yellow and blue jersey.
The Red Bull-Bora Hansgrohe pair emerged from a 60-man breakaway on the final steep climb to the finish in Crest Voland alongside Norwegian Tobias Johannessen.
"We both knew how strong we both were and the situation just played perfectly," said Tuckwell, 21, who said he is not thinking about potentially winning this prestigious race when it finishes on Sunday.
"This is my first year as a pro, I just need to enjoy it to be honest. I came into this race not looking to get any results and just have fun."
Tuckwell pushed the pace, knowing that he would take the leader's jersey, while Van Gils pipped Johannessen in the sprint finish to claim the stage honours at the end of a 182km slog from Saint Vulbas in southeastern France.
"It's one of the most beautiful days in my career," said Van Gils. "To win here in the (Tour Auvergne-Rhone-Alpes) and in a region I really love –- my girlfriend is from here -– today we passed a lot of my training roads, so I'm really happy about it."
He added: "We were without a big leader... but to win a stage and take yellow I think is really big."
Behind the stage winner, teenage French prodigy Paul Seixas and Mexican Isaac Del Toro gained time on their most dangerous rivals in the overall standings.
They came home in 20th and 21st places, 3min 15sec after the stage winner, with Seixas, 19, moving up to seventh overall, 3:06 behind Tuckwell.
Del Toro, 22, climbed to 10th at 3:22.
American Matteo Jorgenson lost 13sec to the two young favourites for the final victory, but is the best-placed of the overall contenders at 2:34 in fourth.
Lidl-Trek pair Juan Ayuso and Mattias Skjelmose lost 22sec to Seixas and Del Toro but sit between them in eighth and ninth overall.
BRUTAL MOUNTAINS TO COME
French duo Bruno Armirail and Guillaume Martin, who were part of the breakaway and finished just over a minute behind Van Gils, have moved up to second and third, respectively.
But it was a terrible day for Netcompany Ineos teammates Oscar Onley and Kevin Vauquelin.
Briton Onley, 23, crashed on the short descent between the day's final two climbs and finished almost half an hour down.
Vauquelin gave up 1:32 to Seixas and Del Toro as he finished alongside Alex Baudin, who had started the day in the yellow and blue jersey.
The French pair fell to 14th and 15th overall.
The day started with a huge group of 60 riders breaking off from the peloton with almost every team represented.
They built up a lead of five minutes at the foot of the two final climbs in the last 20km of the stage, at which point it was clear that the stage winner and the new overall leader would come from the breakaway.
The overall contenders only sprung into life on the final climb when Seixas accelerated about 4km from the line.
Del Toro and Jorgenson were the only ones able to follow initially, but the American cracked with just over 2km to go.
But Del Toro stuck doggedly to Seixas's wheel, providing an appetiser of the battle for overall victory to come in the final two stages.
Saturday and Sunday's stages are shorter at 133km and 120km, but they are brutal mountain routes with several long and punishing climbs and two summit finishes at an altitude of more than 1 500 metres.