Irish riders missed out on the top 50 in the men's elite road race at the UCI World Road Race Championship as France's Julian Alaphilippe earned a dramatic win in Imola after a late charge.

His brutal acceleration on the last climb left his rivals in his wake and the Frenchman eased to the line in a time of 6:36:34, 24 seconds clear ahead of Belgium's Wout van Aert to claim the world championship title on Italian soil.

Switzerland's Marc Hirschi pipped Poland's Michal Kwiatkowski in a photo finish for third just behind Van Aert who had to settle for silver.

Ireland's Nicolas Roche, part of a four-strong Irish squad, finished 51st in the 258.2km road race as just 88 of the 177 riders in the peloton completed the race.

Fellow Team Ireland members Ben Healy and Ryan Mullen did not finish.

"I think I rode a pretty decent race, just the legs let me go in the finish," said Roche.

"I was always up the front, Ben was around me for quite a long time and I just faded near the finish when the race really really started. I was just a little bit short."

Alaphilippe timed his late attack perfectly to give France its first rainbow jersey since 1997.

Three years after coming close in Bergen, Norway, when he was reined in with one kilometre to go, Alaphilippe benefited from top work by the French team, with Guillaume Martin covering their opponents' attacks on the penultimate ascent.

As Alaphilippe turned on the power 12km from the finish on the last of nine 28.8-km laps, only a handful of top riders - Jakob Fuglsang, Hirschi, Van Aert, Primoz Roglic and Michal Kwiatkowski - were left to chase.

They were unable to catch him before the final kilometres on Imola's former Formula One track, where they started to prepare for the sprint for second place, leaving Alaphilippe to celebrate the title.

"It's hard for me to say something. I want to say thank you to all my team mates who believed in me today," a tearful Alaphilippe, the first Frenhcman to win the title since Laurent Brochard 23 years ago, said.

"We did a great job. It was the dream of my career. I came so close already but never made it to the podium. I came with a lot of ambition, it's just a dream come true."