"I have been a Genoa fan since birth, my father is Genoese, I played for Genoa (youth team)," Marras said. "But I celebrated because after a goal you have to celebrate, now I'm with Alessandria, but I'll always carry Genoa in my heart.
"With grit, sacrifice, and team spirit you can play anyone anywhere. The coach (Angelo Gregucci) is instilling in us a winning mentality, he has united the group, and we owe a great part of this to him."
Leonardo Pavoletti headed in Diego Perotti's free kick in stoppage time to force extra time.
In Milan, Inter took the lead in the first half when Palacio turned a deflected Juan Jesus cross into an empty net.
Cagliari could have equalized early in the second half as Fabio Pisacane's glancing header crashed off the base of the left post.
Brozovic all but sealed the match with 20 minutes to go with a stunning strike from outside the area into the far corner, giving young goalkeeper Alessio Cragno no chance.
The midfielder was instrumental in the third goal, too, with an effort that came off the right post, and the rebound was turned in by his Croatia teammate Perisic.