The 28-year-old displayed admirable athleticism to outrace a Fiorentina defender to pick up a sweet crossfield effort from Slovakian midfielder Juraj Kucka.
Boateng then approached the box with maximum confidence and, outfoxed the onrushing Fiorentina goalkeeper Ciprian Tatarusanu before stabbing home to seal the points for Milan who were under pressure to win.
He thanked both coach Sinisa Mihajlovic and president Silvio Berlusconi for the confidence they have shown in him.
“It was an important match for us for many reasons,” Boateng told Mediaset Premium after the game against Fiorentina.
“We wanted to win and we are happy.
“I want to thank the coach and the president for the confidence they have in me.
“Scoring at the San Siro is a perfect emotion.
“It was a win for all the Milan fans.
“Now I want to celebrate with my son and my girlfriend.”
The victory moves the Rossoneri up to sixth place and within three points of Roma, with a trip to Empoli up next.