Napoli have the chance to further extend their lead at the top of Serie A on Saturday when they travel to Bergamo for a top-of-the-table clash with Atalanta in a bumper weekend in Italy's top flight.
Balde’s effort helped Claudio Ranieri’s men return to winning ways after losing to Juventus and securing a draw against Benevento.
The Senegal winger opened the scoring in the 31st minute of the encounter with a fine header after receiving a sumptuous assist from Gaston Ramirez.
Six minutes later, however, Fiorentina levelled proceedings through Dusan Vlahovic, who fired home his effort from close range.
Fabio Quagliarella then scored the match-winning goal in the 71st minute after he was set up by Antonio Rosati.
Balde featured for 89 minutes in his 12th appearance across all competitions for Sampdoria before he was replaced by Mehdi Leris.