go up against
go up against (someone or something)
1. To face a particular competitor, trial, or test. I can't believe I have to go up against the valedictorian for this award—obviously, she's going to win!
2. To oppose or come into conflict with someone or something. The lawsuit is going up against a tradition dating back nearly 200 years. They are just a small band of rebels going up against an entire empire. There's no way they can win!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
go up against someone
to compete with someone; to face someone in competition. She is going up against Rodney in the spelling bee. The champ went up against the challenger in a match last Friday.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.