Rennes have claimed three points from their second Ligue 1 game of the season following a 6-2 defeat of visiting Evian TG at the Stade de la Route de Lorient.
Rennes opened the scoring in the seventh minute when Ola Toivonen converted from close range as he made use of Pedro Henrique's neat headed pass.
Evian hit back, however, as Gianni Bruno found Daniel Wass in the centre of the box and he leapt to convert a headed effort into the top left corner of goal.
The hosts were able to restore their lead after 35 minutes when Romain Danze produced the perfect set-piece delivery, allowing Mexer to notch the third headed goal of the game.
Danze was at the centre of things again just before the break when his assist fell to the feet of Mexer, who lashed in a standout effort from outside the box to make it 3-1 at half time.
Rennes effectively confirmed their three points in the 57th minute as Toivonen drilled home from the centre of the box, having been picked out by the impressive Danze.
Things were to become even more embarrassing for Evian when Paul-Georges Ntep grabbed his side a fifth with just under 15 minutes remaining, before Wass grabbed a mere consolation in the 83rd minute.
The scoring wasn't over, though, as Ntep completed his brace with a rifled shot into the top corner.