Pull a Johnmarc

Few and far between, people named Johnmarc are simply not clutch.

To "Pull a Johnmarc", would would be handily winning a competitive sport or game for the majority of the match only to lose at the last moment due to a stupid mistake. This can happen in situations where maybe you've gotten a large lead over your opponent and suddenly decide to stop scoring (or fail to) and give up on the idea of winning. Much like the verb, "to throw", where someone will lose a game after having obtained a sizable lead. This can also be used in a situation where you are fully capable of doing something but utterly fail to succeed.