Giuseppe Rossi gave the visitors the lead on the hour mark, but late goals from Esteban Cambiasso and Jonathan completed the comeback, which leaves Inter joint second with Juventus and Napoli in Serie A.
And Mazzarri is surprised by the quickness of the turnaround, as a few months ago the club finished ninth in the league and already he is seeing signs of promise for the Nerazzurri, although admits they did not have it all their own way against the Viola.
“You could see we were affected for five minutes by that [Rossi] goal, but then we shook off the tension and in the end deserved this victory,” he said. "It was a struggle sometimes against a very strong team with real quality.
“Fiorentina play very tight and that makes it look as if they have more possession, but the statistics showed it was in the end 52 per cent to our 48, so the difference was minimal.
“Their only real scoring opportunities were created by our mistakes, whereas we had the chance to finish off two really good counter-attacks in the first half alone.
“We tried pressing Fiorentina high up the pitch, but they are so good in terms of technique that it was difficult to shake them up. We need to grow, but thankfully these lads are achieving something exceptional with the time I’ve had to impart my ideas."
Goalscorer Cambiasso also echoed his coach’s sentiments, explaining that the nature of the result meant that Inter had rediscovered their character.
“You can see that Inter have an identity once more and if that is accompanied by results too then it’s even better,” he said.
“Tonight we had a great reaction to going behind. The team is united and the fans can go home happy. Fiorentina really pressured us in the first half, but we knew they couldn’t keep that tempo up and struck at the right moment.”
When asked if Inter’s victory sent a message to their title rivals, Cambiasso replied: “No, we’re sending a message to ourselves.”
The Argentine went on to dedicate his strike to his new family, after his wife gave birth during the week.
He concluded: “I dedicate this goal to my son Dante and to my wife, as she was the one who struggled and worked to bring him into the world. This victory ends three crazy days."