Saint-Etienne went third in Ligue 1 on Sunday after a late winner from Romain Hamouma propelled them past relegation threatened Evian 1-0 and into temporary possession of the final Champions League spot
The 'Green Devils' who memorably lost the 1976 European Cup final against Bayern Munich in Glasgow overtook neighbours and arch rivals Lyon on goal difference, ahead of the latter's tricky trip later on Sunday to Reims.
The fallen giants are one of the most successful teams in French football but the last of their 10 league titles was back in 1981.
Hamouma headed home Francois Clerc's cross with just 12 minutes remaining.
Saint-Etienne have also reached the French League Cup final - their first domestic final since 1982 - where they will face Rennes on April 20.
The result piles the pressure on Remi Garde's Lyon who need to take something from their trip to a Reims outfit sitting just one point above the drop zone, if they are to maintain a place in the top three.
Lille could move within one point of Lyon and Saint-Etienne if they take maximum points at home to Lorient, as long as Reims defeat Lyon.
Paris Saint-Germain have a comfortable seven point cushion over Marseille at the top following their impressive 2-0 win at Rennes on Saturday, which was fuelled by Zlatan Ibrahimovic's league leading 26th goal of the campaign.