Ismael Bennacer will be out of action for at least six months after undergoing knee surgery, AC Milan said on Tuesday.

Bennacer, 25, was substituted in the 17th minute of Milan’s 2-0 defeat to Inter Milan in the first leg of the Champions League semi-final last week.

The Algeria international had an operation on Tuesday morning to repair damage to cartilage in his right knee.

Milan will try to overturn their first-leg deficit in the second of two blockbuster local derbies on Tuesday night.