The Rio 2016 gold medallist, who rides for BMC Racing Team, crossed the line in 5 hours 41min 07sec following a pulsating sprint finish.

He defeated Quick-Step's Zdenek Stybar of the Czech Republic, who took second, while Cannondale-Drapac's Sebastian Langeveld of The Netherlands rounded out the podium in third.

Van Avermaet, Stybar and Langeveld broke clear from the pack on the Carrefour de l'Arbre, the final section of cobblestones, with around 15 kilometres to go.

Italy's Gianni Moscon of Team Sky and Trek-Segafredo's Jasper Stuyven of Belgium gave chase and rejoined the lead trio rounding onto the final lap of the outdoor velodrome in Roubaix.

Stybar launched his sprint with only Van Avermaet able to match his acceleration.

The Belgian managed to surpass Stybar and pulled ahead inside the final hundred metres and held on to cross the line first.

It was the first time he has managed to win one of cycling's five prestigious one-day 'monument' events.

"I think that I did everything well and I still had the power to beat Stybar," Van Avermaet told the media after the race.

"I'm really happy.

"For me, the Olympics will always be my biggest victory.

"I was really confident about my sprint because several times I've done a sprint from a small group and at the end of a race I was always one of the fastest guys.

"I came into the track with the thought that I'm going to win this race."

World champion Peter Sagan suffered two punctures after launching attacks to force himself out of contention.

The race across northern France is the third of five one-day 'monuments' this season, and is part of the International Cycling Union World Tour.

Team Sky rider Michal Kwiatkowski of Poland won the first of the season at Milan-San Remo while Quick-Step Floors' Belgian Philippe Gilbert won the Tour of Flanders last weekend.

The fourth - Liege-Bastogne-Liege - takes place on April 23, while the Giro di Lombardia concludes the series on September 30.

Earlier on Sunday, Great Britain's Tom Pidcock won the 111km junior edition of Paris-Roubaix.