play someone at his own game—return smb.’s hostile or unfair action with the like:
- Men used to come in the office and I never used to get introduced. So I’ve started playing them at their own game.
play someone’s game—
1. advance a person’s plans or schemes, whether willingly or unintentionally:
- If I want him to give me the information I need, I guess I should play his game.
2. use another person’s unfair practices, especially to gain one’s own ends:
- If playing his dirty game is the only way of winning the election I’d rather lose.
See also: play games with someone / play with someone.