The Italy forward was kicked out of Sampdoria in October for verbally abusing the club president in the latest in a long line of crazy antics and fans worried whether Milan had taken on more than they could chew when he joined them this month.
However, Cassano set up Rodney Strasser for the winner in Thursday's 1-0 victory at Cagliari and played in both Alexandre Pato and Zlatan Ibrahimovic late in Sunday's astonishing 4-4 home draw with Udinese where the leaders had been 3-1 down.
"Simplicity is the best thing in football. Moreover, to play simply is the most difficult thing and only top players manage it," Milan coach Massimiliano Allegri told Sky.
"Cassano today gave us two great assists. When we play around the box he is devastating. Definitely when he is fitter he can play from the start."
Cassano's San Siro debut began in typical style when he insulted the officials from the bench for allowing Udinese's opener, even though Antonio Di Natale was clearly onside.
The livewire went to apologise to the referee at halftime having seen the replay before finally doing his talking on the pitch, using angles and speed of thought to rip open the visiting defence rather than dribbling excessively as he ocassionally did at Samp, Real Madrid, AS Roma and Bari.
"It's been one of those games which happen during a season. I think a draw was the right result," Allegri said, adding Clarence Seedorf did not deserve to be booed by his home crowd.
"I don't think he had such a bad game. It's unlikely we will repeat a defensive display like that."
