Thank you, Sarcie. And if we are talking about a similar situation, having nothing to do with sport, though, what would you use then?
Ex. I know a girl who is very arrogant and snobbish. Eventually she fell in love with a man even more arrogant and haughty. She has finally found her match. Is the red sentence used properly?
What other synonymous expressions are most likely to be used for the same situation?
I don't think to meet one's match is informal. It's a perfectly good metaphor, and can be viewed as belonging to the poetic level of language. Not that informal language is devoid of poetry, but the converse is not always the case.