Saint-Etienne's 32-year title drought ended in the French League Cup final when Rennes was beaten 1-0 with a goal by Brandao on Saturday.
The Brazilian striker capitalized on a defensive mistake from Rennes goalkeeper Benoit Costil to volley home from close range in the 18th minute.
The last time Saint-Etienne won a trophy was in 1981 when it clinched the French league title.
''We're making history,'' Saint-Etienne coach Christophe Galtier said. ''We are going to put on a shelf this beautiful trophy that this club has never won.''
Saint-Etienne dominated French football in the 1960s and 70s.
''We saw tonight the popular enthusiasm around this club. It's because of what the club achieved in the past. We had to rise to the occasion, and we did,'' Galtier said. ''Winning this beautiful trophy is not an end in itself. I hope it's the beginning of a revival.''
Saint-Etienne was tipped as the favorite. It sits in fourth place in the French league and has lost only one game in all competitions in 2013.
On the other hand, Rennes poorly prepared for the final by losing its last four matches in the French league to slip to the middle of the table.
After a frantic start, cautiousness prevailed before forward Pierre-Emerick Aubameyang charged down the left wing to hoist the ball into the box. Costil missed his catch and the opportunistic Brandao flicked the ball into an empty net.
Turning around the match became an uphill struggle for Rennes, which missed through injury its best player, Romain Alessandrini, as well as defenders Kevin Theophile-Catherine and Herita Ilunga.
Rennes was hit by bad luck when striker Melvut Erding picked up a thigh injury and was replaced by the inexperienced Cheikh Diarra in the 25th. However, the Brittany side did not give up.
''When we have a full-strength team, we can compete against anybody,'' Rennes coach Frederic Antonetti said. ''But when we miss two or three players, it's a bit more difficult. It's obvious that we didn't play the final in the best conditions.''
The result was a blow for Rennes which has not won any trophy since lifting the French Cup in 1971.
