Mihajlovic has come in for criticism after his team's disappointing results in recent weeks.
Fiorentina lost 2-1 against Lazio before being held to a goalless draw at Cesena last weekend, leaving them 10th in Serie A.
Viola fans have grown disillusioned with life under Mihajlovic, who is in his second season at Fiorentina.
"Mihajlovic is doing a great job," Gamberini said to www.acffiorentina.it. "He has given character and an identity to the team.
"The criticisms directed at him are unjust.
"We are playing well and against Napoli, Lazio and Cesena we collected less than what we deserved."
Fiorentina have struggled in front of goal, finding the back of the net just once in their last three league games.
With striker Alberto Gilardino still out of action through injury, Mihajlovic will be hoping Santiago Silva can open his Serie A account this weekend.
Silva will play alongside Alessio Cerci and Stevan Jovetic in attack.
Rivals Catania travel to Tuscany in buoyant mood after celebrating their second win of the campaign in last weekend's 2-1 triumph against Inter Milan.
The result lifted the Sicilians to ninth place, one point clear of Fiorentina.
Catania coach Vincenzo Montella has urged his players not to get carried away by last weekend's success.
"We deserved the win and we handed a solid performance against Inter," Montella said. "But we cannot read too much into this victory.
"We have to continue to work hard and do well."
Catania hope to recover midfielder Marco Biagianti for this weekend's trip to Florence with the midfielder struggling with a muscular injury.