Milan lost 3-0, but the victory was overshadowed by the loss to key defender Kjaer in the third minute.
The Danish star suffered an ACL injury and underwent surgery on Friday, ruling him out for the next six months.
“Milan confirms that Simon Kjær underwent arthroscopic surgery today to reconstruct the anterior cruciate ligament and reinsert the medial collateral ligament into his left knee,” a statement posted on their website said Friday.
READ MORE: Ralf Rangnick makes claim against Jurgen Klopp Liverpool’s side ahead of Manchester United arrival
READ MORE: Jurgen Klopp reflects on Thiago Alcantara change as Liverpool consider defensive change
“The operation, which was performed at the Casa di Cura La Madonnina clinic, was a perfect success, Dr Roberto Pozzoni having performed it with the help of the CTS team (Centro di Traumatologia dello Sport – Sports Traumatology Center) of the Galeazzi. Orthopedic institute in the presence of Club doctor Stefano Mazzoni.
“Kjær is doing well and is eager to begin the rehabilitation process immediately. He is expected to be away for six months.
Kjaer finished 18th in the Ballon d’Or standings this week after an exceptional season, including playing a pivotal role in Denmark’s 2020 European Championship semi-final where they lost to England 2-1 in the additional time.
Liverpool have comfortably qualified for the round of 16 in UEFA’s flagship club competition and are expected to rest key players midweek as they prepare for a difficult festive period.
But with Milan needing a win to get out of Group B, they face an endemic Reds side without a key defender.