Barcelona left-back Jordi Alba was at fault for Liverpool's first two goals in Tuesday's 4-0 defeat at Anfield.
The Catalan, who has had an excellent season for the Blaugrana, headed the ball back into the path of Sadio Mane, who found Jordan Henderson, in the seventh minute and his shot was pushed away by Marc-Andre ter Stegen only for Divock Origi to finish the rebound.
For Liverpool's second goal, Jordi Alba was also at fault.
Trent Alexander-Arnold pinched the ball from the left-back out and crossed for Georginio Wijnaldum to fire home under Ter Stegen to make it 2-0.