"He knew he had sent him to the sin-bin and didn't show any empathy for the game. But we didn't get the defence right on Morgan's wing and they scored three tries."
Clermont are now unbeaten in 48 games at home, and Easterby is demanding his side hit back next week when they face current European champions Leinster at Parc y Scarlets.
"We will take a lot from this game, we took a bit of a beating which will be tough to take. The players in there to a man are bitterly disappointed, but this group is still very much alive and we are very much alive in it.
"But next week is a must win game. If you lose your first in Europe, you have to win your second."
The French giants showed no mercy in the second half, snaffling five tries through Lee Byrne, Damien Chouly, Julien Bonnaire and Naipolioni Nalaga along with a penalty try.