With the race win almost certainly Jonas Vingegaard's, stage 2 winner, Julian Alaphilippe, 7th in the general classification at the start of the day at 3:48 down, managed to get up the road in the break.
With 30km to go he was part of a 5-rider group 1:37 ahead of the main bunch alongside Tiesj Benoot, Jonathan Castroviejo, Giulio Ciccone and Clément Champoussin.
On the penultimate climb of the day, Ciccone wasted little time making his move with only Alaphilippe able to follow.
With 20km to go, Ciccone made a second move and this time Alaphilippe had no answer to it.
Down the road, Adam Yates launched an attack in an attempt to hold on to his second place overall with Jonas Vingegaard swiftly on his back wheel.
With the GC battle lighting up only Ciccone remained ahead of the main favourites at the top of the climb with the Italian 30 seconds clear of the likes of Yates, Vingegaard, O'Connor and Hindley.
Going over the top however, Movistar Team's Antonio Pedrero attacked from the bunch, hoping to catch Ciccone on the descent.
As they reached the final little kicker up to the line, Ciccone had 37 seconds on Pedrero and 56 seconds on the Yellow Jersey group.
When Vingegaard finally made his move, with 1km to go, once again not one of his rivals could match him. The chase was then on for the Jumbo-Visma leader to try and catch Ciccone on these ridiculously steep gradients.
It was the Italian from
Trek - Segafredo however who was holding the gap, inching closer and closer to a brilliant stage win.
Turning the final bend, he was allowed a moment to savour the victory before Vingegaard came racing home for second on the day and the overall win.