Racing on home roads, the French squad was prominent throughout the 232-kilometre race, and eventually placed three riders in the top ten, as Alaphilippe took the silver medal, Samuel Dumoulin finished fourth and Tony Gallopin came home in seventh.
In the small group sprint in the finale on the Côte de Cadoudal, however, there was little to be done against the powerful Sagan, who ripped clear inside the final 100 metres to take the win, while Alaphilippe came past Dani Moreno (Spain) to take second place.
"The French team did a good race. We were all motivated to take this first ever European pro title. I think we made a real impact on the race. We had three cards to play with Tony Gallopin, Samuel Dumoulin and me, and we were all there in the finale," Alaphilippe said afterwards, according to L'Équipe.
"We took on our responsibilities but we were up against a Peter Sagan who was clearly the strongest. I have nothing to regret, even if all of these places of honour that I'm picking up are becoming a bit tiresome."
After fourth place at the Rio 2016 Olympics, second at Liège-Bastogne-Liège last year and at Flèche Wallonne in each of the past two seasons, Alaphilippe has come maddeningly close to a series of major victories. His defeat to Sagan in Plumelec was reminiscent of his second place behind the world champion on stage 2 of this year's Tour de France in Cherbourg.
"That could become annoying but I haven't finished behind just anyone," Alaphilippe said of Sagan. "But above all, I can't content myself with that in the future. Sagan was clearly the strongest, but he's not superhuman either."
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French national coach Bernard Bourreau felt that his team had been left to do the bulk of the work at the head of the peloton as it raced before home crowds in Brittany.
“The foreign teams left us to work even though everybody knew that Peter Sagan was the strongest. We would have needed more people to attack him in the last five laps. Instead of that, every team thought of its own personal interests. It's a shame," Bourreau said. "But we have nothing to reproach ourselves for. This second place behind a champion like Sagan means something."
