The late attack from Matteo Trentin lasted 14 kilometres to the finish and over the Col de la Sentinelle with the European road race champion able to celebrate in style as he crossed the finish line.
"It was really an emotional finish, I've only won two races in my whole career alone," said Trentin. "To do it here at the Tour de France with this finish line, with this group in front. It was a super strong group, it was just amazing to ride away on a climb that nobody would put in Euros."
Trentin made his move on the flat after a series of attacks split up the smaller group contesting the stage win, and was never seen again as he powered away to a famous victory.
"With a big group, it was always the case that someone would anticipate or it would go in a small group," said Trentin. "I was watching for the right move where the strong guys went. Chris Juul (Jensen) went across and then when I was there he just managed behind to stop moves.'
"I try, actually a few times because there was no collaboration and I knew if I got a ten second gap then maybe they start to watch each other and with the legs I have I could finish it off."
In the early kilometres, Thomas De Gendt dragged a large group of 32 riders off the front of the peloton and despite the efforts from teams that missed the break, the initial large move stuck.
Still desparate to make the escape, Total Direct Energie laboured on the front until eventually the elastic snapped and the break's advantage went out to a maximum of 15 minutes as Deceuninck-QuickStep set a relaxed tempo with no threats to Julian Alaphilippe's yellow jersey in the move.
Skirmishing among the breakaway started 37 kilometres from the finish before the final, category 3 ascent of the Col de la Sentinelle.
The front group fractured into an attack of 11 riders into the finish in Gap, Trentin launching clear before the base of the final climb. Pierre-Luc Perichon (Cofidis) set off in lone pursuit as the Italian escaped up the road.
Trentin pushed out his advantage to 40 seconds over the group of chasers as he reached the summit of the Col de la Sentinelle, with Kasper Asgreen (Deceuninck-QuickStep) pushing past Perichon as he attempted to chase down Trentin on the descent into Gap.
But noone could stop Trentin and he cruised over the line to claim Mitchelton-Scott's fourth stage win of the Tour.
The race favourites cruised over the final climb and descent as the general classification remained unchanged, the only action an altercation between Luke Rowe and Tony Martin which resulted in their disqualification from the race.