Nathan Redmond's solo effort put the Blues ahead after 24 minutes, with a Damien Delaney own goal doubling their advantage before Ravel Morrison and Shane Ferguson both struck in the second half.
The win - City's third on the trot - moved them within eight points of the top six in the Championship on 52 points.
"We are just looking at the clubs directly above us to try and peg them back," said Clark.
"We are also not being arrogant or ignorant and thinking we are out of what is going on behind us as well.
"I am thinking those teams behind us will carry on their good form tomorrow and I am still in thought process that it might be a record number of points needed to keep you in the division.
"We're well aware of everything around us in the division and I know it is a cliche but it is important we take it one game at a time."
On the result, Clark added: "When you come to a place like this you expect it to be tough and a close match.
"It was but not in my wildest dreams did I expect the margin of victory to be that big and, in all honesty, it was fully deserved as well. It wasn't a fluke.
"We had 11 fantastic performances today. You can't come to a place like this and carry any passengers."