Quickfire goals from Adam Forshaw, a penalty, and Marcello Trotta midway through the first half did the bulk of the damage, with Sam Saunders adding a third after the break after Joel Garner missed a penalty for the hosts.
Warburton said: "I think it sends out a powerful message, it is not an arrogant one that we have come here and done a good job and the boys have got a self belief now.
"That is the key for me. We know about them technically, tactically and physically and they are in good shape. But can they believe in themselves? I think that it is getting the head right.
"We thought to ourselves what problems do they pose and we saw the wing-backs going forward but there was space behind with three defenders and they were vulnerable, in our opinion, and that is really what we tried to do and hopefully that worked out very well for us.
"If you fall beneath your standards you run the risk of losing your shirt. It is a squad game and we entirely rely on the squad it is very important to highlight that point."