Ola Toivonen, close-season signing Mexer and substitute Paul-Georges Ntep all notched doubles on a memorable day at the Stade de la Route de Lorient.
Daniel Wass got the visitors back on level terms after Toivonen's close-range opener, but he and Evian had plenty to think about by the time he completed a brace of his own, with this thrashing coming on the back of last weekend’s 3-0 loss to newly-promoted Caen.
Substitute Ladislas Douniama came off the bench to score three minutes into stoppage time as Guingamp left Lens with a dramatic 1-0 victory, opening their account for the season and condemning their hosts to back-to-back defeats.
Wissam ben Yedder scored a brilliant free-kick to ensure Lyon's wretched record at Toulouse continued.
Lyon had not scored at Toulouse in Ligue 1 since 2005 and, although Alexandre Lacazette remedied that sorry statistic by finishing a move he started 15 minutes from time, the hosts were able to hold out for a 2-1 victory.
Jean-Daniel Akpa-Akpro lifted a delicate 10th-minute finish over Lyon goalkeeper Anthony Lopes to opening scoring, then Ben Yedder's viciously dipping strike on the stroke of half-time proved too hot to handle.
There were two early goals at the Stade Saint-Symphorien, as newly promoted Metz remained undefeated with a 1-1 draw against Nantes.
Jordan Veretout blasted Nantes into a third-minute lead, but Yeni Ngbakoto levelled from the penalty spot after Juan Manuel Falcon was fouled.
Elsewhere Lorient and Nice played out a goalless draw at the Stade du Moustoir.