Florian Vachon (Bretagne-Séché Environnement) made a break for a solo victory late in the 208.2km race from Saint-Ghislain, but was caught and passed by French compatriot Feillu on the finishing straight.
However Belgian Vangenechten was there too and shot past in the final 150 metres before holding on for the win.
The peloton caught Vachon too, with Andris Smirnovs (Doltcini-Flanders) third ahead of Jérémie Galland (Sojasun) and Egidijus Juodvalkis (Crelan-Euphony).
An early four-man break featuring Dominique Cornu (Topsport Vlaanderen-Baloise) stayed out for the majority of the stage before being caught with 50km remaining.
Vachon and Francisco Ventoso (Movistar) attacked but were reeled in quickly before Vachon's solo effort.