Don't steal material. I know the temptation, sometimes you see a joke that would fit just perfect with something you have, man oh man it would sell the whole piece etc etc
There's no excuse good enough. If you see a joke that is like that it simply means you need to write and think about your act even more. It's a muse calling you out, that's all.
You should perhaps thank the comic for opening a new level for you or inspiring you and let it go at that, take the lesson but DON'T by any means, take the joke.