Cassano has impressed since arriving from Sampdoria.
"I want to thank Milan because in a moment of great difficulty for me, they took a chance on me," said Cassano.
"This is my last opportunity, so I won't be deceiving the people who believed in me. I hope I will be playing here for a long time. I think, and I'm pretty sure, that this will be the last team I play for.
"I give my complete availability for a unique aim which is to win."
Cassano admits that his best is yet to come.
"I think in 25 days I will be at the top of my game in order to play at the best level in the final four months of the campaign," he said.