Usually, it's when a guy that is generally beloved among hardcores/in smark circles has a good match with a guy who is generally disliked. In most cases it is used, it's just confirmation bias. This is definitely the case when it comes to the Reigns matches against Bryan and Lesnar.
It's not usually used in this way here as much as it is in other places, by Meltzer, etc. but I think in most cases, that's what is. "This guy is supposed to suck, but he just had a great match. It must be because the good worker he was in the ring with carried him."