The on-loan striker dedicated his double in Sicily to his family and girlfriend for standing by him during his struggles at San Siro
The Italy international joined the Rossoneri from Juventus last summer for a reported €12 million but managed just one Serie A goal for the San Siro side before being shipped out on loan to the Artemio Franchi earlier this week.
Matri wasted little time in silencing his critics, though, setting up a goal for Mati Fernandez before then hitting a double to earn Fiorentina a 3-0 win at Catania.
"It has been a long time since I've had an afternoon like this," the 29-year-old forward told Sky Sport Italia.
"The last few months have been difficult, so it's only normal that I lost a little bit of composure. It was my fault, I did not settle [at San Siro].
"Those who stood by me know how hard I tried [at Milan], so now I dedicate these goals to my family and my girlfriend."
The only disappointing aspect of Matri's otherwise dream debut, though, was an injury that could jeopardise his participation in the midweek Coppa Italia meeting with Siena.
"I felt a slight calf strain," he explained. "So, tomorrow [Monday] we'll do the tests and see what it is."