It could mean that when someone wants to challenge you, you have the balls to fight back, or to keep up the pace and become, either a winner, or prove them wrong for having the tendency to challenge you. Its a term that firstly was announced of game horses and meant that this horse that I'm counting on can give me my money back, cause I simply have big hopes and expectations from it. Usually this phrase has a lot of different meanings but this one is the most concrete.
You see these guys over there working out?
They'reweak as fuck.
I bet none of these phonies can give me a run for my money.
I am a bodybuilder and I'm working out for fun. It's my life.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.