How to Get an Audience Back When You're Losing Your Audience

I've seen a lot of stand up comedians, some well known, some no names. But i have been present only one time for a comedian who just bombed. And once he started losing the audience, it just didn't matter how good his material was, he just couldn't get them back. I think in order to to get the audience back, you really need to be on top of your game. You know, you have to be all there.