Vannes booked themselves a last-16 tie against St Etienne as they saw off Ligue 1 strugglers Grenoble 4-3 after extra time in a thrilling Coupe de France clash.
The second-division side took the lead in the 16th minute through Franck Djadjedje but it seemed as if natural order would be resumed when Jimmy Juan and Nicolas Dieuze scored within minutes of each other to put Grenoble in front with 10 minutes remaining.
Goals from Biagui Kamissoko and Abdoul Camara left Vannes on the verge of an upset but Sandy Paillot pounced in the second minute of stoppage time to send the game to extra time.
However, Pascal Delhommeau struck with five minutes remaining to ensure Vannes' cup dream continues.
Another Ligue 2 outfit took Auxerre all the way but there was to be no fairytale ending for Sedan as they were eliminated 3-0 on spot-kicks after the match had ended 1-1.
Ireneusz Jelen had opened the scoring for the hosts just before the half-hour mark with Alexis Allart levelling matters three minutes from the break. Auxerre will meet either Nancy or Plabennec.