He launched a thunderous breakaway on the final kilometre to the finish, just as he had done earlier this year in the Tirreno-Adriatico to arrive solo at the finish with a late attack.
The EF Education-EasyPost rider held up a lucky charm made by his son as he celebrated the win ahead of Andreas Leknessund (Uno-X Mobility) and Damiano Caruso (Bahrai Victorious) while Jonas Vingegaard (Visma | Lease a Bike) comfortably retained his Maglia Rosa.
The 34-year-old formed a fine partnership with Movistar's Einer Rubio with 20 kilometres to go, as the pair led up the final 8% incline towards the finish. But Valgren had plenty of patience as he made his decisive move 500 metres away from the finish line to speed away from the pursuing bunch, not waiting for a sprint finish to decide the race, as Rubio was finally caught.
"I'm actually quite slow in a sprint", said Valgren after the win, according to TV2 Sport. "Adam Blythe asked me this morning about my maximum power, and I'm almost embarrassed by it. It was my chance to attack. When I have good legs, I'm good at it."
"It was a strange day in such a large group. We did not cooperate well. I was frustrated that we didn't really race until the end. It was really hard. I was on the border and didn't get food for some time. The car was far behind. I was afraid of going sugar cold. Fortunately, the stage was not 500 m longer."
"I have been missing this win. I deserve it. I have told other media that my career has been good, but I have been missing a grand tour stage. Today it arrived in Italy. Apparently, I drive well in Italy. I am happy to be here."
The race continues on Thursday with the 18th stage which is a 171-kilometer route from Fai della Paganella to Pieve di Soligo