Whitbread, 27, said: "It is not nice to get beaten in the cup and we had it in the back of our minds not to let it happen again.
"We went about it the right way. They put us under pressure early on but we controlled it with our pace, passing and movement.
"We never stopped and looked strong even when they got the goal back. Once we made it 3-1, we were in control from then on."