Fares Chaibi struck late to help Toulouse past second-tier Annecy and into a first Coupe de France final for 66 years with a 2-1 win at Parc des Sports.
The Ligue 1 visitors had looked destined for penalties heading into the final stages against their Ligue 2 hosts, before the substitute rode to the rescue.
A horrendous defensive misread by Annecy allowed him to head past goalkeeper Thomas Callens into an open net and send his side to a first final since 1957.
Toulouse had originally seized the lead in the first half through Zakaria Aboukhlal, with the winger's low header drifted home off a Branco van den Boomen cross.
But their opponents had equalised on the stroke of half-time through a penalty for Alexy Bosetti, after Gabriel Suazo was deemed to have fouled him inside the area.
The result means Philippe Montanier's side can look forward to a clash with defending champions Nantes at the Stade de France next month.
