I think it's kind of a sporting expression. If I'm not mistaken, the quote you refer to involves spotting or spying someone making an error. That is, you "catch" someone in a mistake. If you hadn't "caught" him, he might have gotten away with it. I can't think of a synonym.
In some sports, eg., baseball, they use "good get" as a synonym for "good catch," but it's a fairly new expression. The difference between this and your example is that in baseball you job is to catch the ball - even the difficult ones. When you catch someone making a mistake, you may or may not be looking for violators. You may just "happen" to see it.
Of course, "Good catch!" could refer to fishing.