Vidic admits he and his team-mates will be spurred on by last season's collapse, which sealed an embarrassingly early group-stage exit for the Old Trafford club.
The Serbian said: "We have a lot of things to prove. Last season, we were too confident in the group stage.
"We lost some points but we thought we were going to go through. The boss made it clear last season wasn't good enough. But we know that ourselves."