Outnumbered by three rivals from the same team, including the mighty Wout van Aert, US rider Neilson Powless thought he had a million to one chance of winning a four-man sprint finish in the Dwars door Vlaanderen race.

Somehow, he managed to beat the longest of odds.

Powless powered to the line past van Aert, who was led into the sprint by his Visma-Lease A Bike teammates Tiesj Benoot and Matteo Jorgenson, trying to ensure his victory in Wednesday's traditional 'Across Flanders' warm-up to Sunday's Tour of Flanders 'Monument'.

"I thought I was riding for second place. I can't believe it. I'm so happy," Powless said. "I felt really strong today but I didn't think I had a chance to win from that group."

Van Aert is one of the favourites for the Tour of Flanders classic, which has a stellar line-up. Tadej Pogacar and Mathieu van der Poel also will start on the gruelling cobbled roads.

On Wednesday, van Aert was left bowing his head 20 metres from the line seeing Powless clad in the vivid pink jersey of the EF Pro Cycling team had left the yellow-clad Visma trio trailing.

They were left alone soon after a decisive attack by Visma with more than 70km left.

It was another disappointment for the Tokyo Olympics silver medalist van Aert in Dwars door Vlaanderen, where a bad crash one year ago ended his program in the spring classics.