AC Milan midfielder Mathieu Flamini underwent knee surgery on Tuesday and is set to be out of action for almost six months, the Serie A club confirmed.

The 27-year-old Frenchman damaged his right knee during Milan's 2-1 win over Juventus in the Berlusconi Trophy earlier this month .

A Milan statement read: "Flamini has undergone surgery on his right knee to repair his anterior cruciate ligament.

"The estimated time of recovery is five to six months."

Flamini, who made 22 league appearances to help AC Milan win the scudetto last season, will miss the first half of the season, including the group stages of the Champions League.