Starting the day two points and one place better off than Les Canaris, Auxerre simply needed to match or better Nantes' result against Angers when they welcomed Lens to the Stade de l'Abbe Deschamps.
However, Christophe Pelissier's side were facing the far more arduous task against the soon-to-be Champions League contenders, even with Franck Haise's side only playing for pride on the final day.
Meanwhile, Nantes hosted already-relegated basement side Angers at the Stade de la Beaujoire, where a first-half Ignatius Ganago strike propelled Les Canaris to the 1-0 win they so craved - moving them onto 36 points for the season.
Fans invaded the pitch at full time, during which Auxerre's clash with Lens was still being played, but AJA were all but condemned to the drop thanks to an Alexis Claude-Maurice brace before M'Baye Niang pulled one back.
There was to be no reprieve for Pelissier's side, though, as Lois Openda rounded off the scoring in a 3-1 win for Lens, who officially relegated Auxerre after just one season back at the top level.
Auxerre will join Angers, Troyes and Ajaccio in the second tier next season, and elsewhere on the final day, champions Paris Saint-Germain ended their season in dismal fashion with a 3-2 home loss to Clermont.
Monaco's 2-1 home loss to Toulouse also ended Les Monegasques hopes of European football, as Lille and Rennes clinched fourth and fifth place respectively.