By bringing on a centre half?? No, not when there were a load of attacking options to play alongside Vernon who was clearly in good touch. As far as Celtic being on the ropes is concerned, that is overstating it, they were most definitely vulnerable but not "on the ropes", we didn't create very much at all and missed what we did have.
I agree about Mawene though, looked handy and by far the best I've seen him.