Jonathan Clauss had put Nice ahead just after the hour with a brilliant finish, only for Zuriko Davitashvili's penalty to restore parity at Allianz Riviera 11 minutes from time.

But with extra-time looming, three goals in 11 minutes late on by substitute Boudache and Wahi sealed the win for Claude Puel's side, which avoided relegation to the second tier.

Nice weathered an early storm and almost took the lead when Mohamed-Ali Cho's deflected shot dropped to Wahi, but his attempt on the slide clipped against the right post.

Gautier Larsonneur then made two excellent stops at the end of the first half to deny Dante's header from point-blank range before getting down to repel Antoine Mendy.

It was then Saint-Etienne's turn to hit the woodwork nine minutes after the restart through Lucas Stassin, and the hosts made the most of their reprieve in the 61st minute.

A long throw into the box was not dealt with by the Saint-Etienne defence, with the loose ball finding its way to Clauss, who rifled a fierce strike in at Larsonneur's near post.

But Saint-Etienne drew level when Mendy handled the ball in the area, with Davitashvili tucking away the spot-kick, but the visitors' joy instantly turned into despair.

Just under two minutes later, Boudache curled the ball into the bottom-left corner from the edge of the box, before Wahi collected Tom Louchet's pass to score.

However, Nice and Wahi were not done there. With Saint-Etienne looking to find a way back into the game, they were caught out on the break in second-half stoppage-time, with Wahi racing clear and dinking over Larsonneur to seal the victory.

In what has been an underwhelming Ligue 1 season for Nice, it produced a fine display when it mattered most, while also ending a seven-game winless run at home in all competitions in the process.