The Bora-Hansgrohe rider beat Daryl Impey in a sprint in Mataró on the penultimate stage of the Catalan race, his first victory of the season.
Sagan suffered from Covid-19 during February and was forced to spend multiple weeks off his bike, leading to him missing Opening Weekend.
After belatedly beginning his 2021 campaign at Tirreno-Adriatico and then placing an impressive fourth at Milan-San Remo, Sagan opted to continue his season in northern Spain to prepare himself for Flanders and Paris-Roubaix, if the latter race is given the go-ahead.
He didn’t, however, expect to be winning this week. “I am pretty surprised,” he said. “I am happy for this [win].
“I have to say thanks to all of my team-mates who did a great job during the whole day.
“I know that Impey should be the fastest guy from this group here, and I controlled the front alone and after the last roundabout I started the sprint and it was a pretty high speed from there.
“It is the first victory for me and it’s come earlier than I expected after Covid. That’s why I am very happy and surprised by this.”
The last time the three-time world champion won a European race this early in the season was in 2018 when he triumphed at Ghent-Wevelgem, the race that this year he chose to skip in favour of Catalunya.
“How I have been past the last few months, it’s not been an easy start to the season,” he added.
“But I said I have to try the hardest races as possible and that was Tirreno, Milan-San Remo and it continued here.
“It has been important here. It’s why I skipped Belgium and the Classics. I have done [E3] Harelbeke and Ghent for 11 years.
“But I decided to come here, train in hard conditions with lots of climbs and in good weather.”
There is a possibility of another sprint finish in Barcelona tomorrow, but now all attention switches to Flanders, the cobbled Classic that he won in 2016.
Is he confident? “Well, yeah…” he smiled. “After today I have to be optimistic.
“When I finish this race it’s about recovering and we will see in the Tour of Flanders how I feel.”