But the day belonged to Owain Doull and his fellow escapees Romain Combaud (Nippo Delko), Ian Garrison (Deceuninck - Quick Step), and Matthias Brandle (Israel Start-Up), the Welshman taking just his second career victory.
"This is my first professional win in Europe," Doull said. "I’ve won one race before in Australia (at the 2019 Herald Sun Tour).
"It’s nice to get the team’s first win of the year and it’s a good sign before the classics."
"It was a hard day and we worked together really well as a four. I was quite confident with the finish and I knew most of the guys, and I had good legs so I was quite happy to wait for the sprint.
"Around the 30km (to go) mark when we still had around four minutes I thought we had a chance. If we stayed together on the climb, I knew the run-in from last year was really fast. If we stayed as a group and rotated fast I knew we’d have a chance. With around 2 or 3km to go I knew we’d stay away – then it starts to get a bit tactical and thinking about the sprint."
Quintana, winner of the 2014 Giro d'Italia and 2016 Vuelta a Espana, took to the podium with a beaming smile after securing his first stage race victory since 2017's Tirreno Adriatico.
"My Arkéa-Samsic team were dazzling today," he said. "And having achieved this opens a new era for the entire team.
"I’m in good shape, and on the next races I’m going to compete in, I can hope for good things.
"We are all having a great week with this very nice victory for Nacer, obtained on the first day in the sprint and which put the Arkéa-Samsic team on the right track straight away during this competition."
The stage started explosively with numerous attacks including Australian Chris Harper (Jumbo-Visma) getting away with a number of riders. But Doull, pulled clear and stayed away after Thibaut Pinot claimed the first KOM of the day after 30kms raced.
With Astana first working to reduce the gap over the final KOM for no apparent purpose, and Sunweb later trying to bring down the gap to get one of their faster men to the line, the peloton almost caught the breakaway but left their run just that little bit late.
Need more? Watch the Stage 4 replay: