play (one's) ace (card)

play (one's) ace (card)

To make use of a resource that one knows or hopes will ensure a decisive and successful outcome. She played her ace card during the debate by bringing up her opponent's earnings from investment firms that contributed to the global recession just a few years prior. The prosecutor then played his ace, showing security camera footage clearly placing the suspect at the scene of the crime.
See also: ace, play
Farlex Dictionary of Idioms.

play your ace

If you play your ace, you do something clever and unexpected which gives you an advantage over other people. Note: In many card games, the ace is the card with the highest score. He told us that he was a very important criminal lawyer who had defended men on heavy charges. And then he played his ace. He also had a number of clients who were involved in the gold business.
See also: ace, play
Collins COBUILD Idioms Dictionary, 3rd ed.

play your ace

use your best resource.
See also: ace, play
Farlex Partner Idioms Dictionary

play your ˈace

use your best argument, etc. in order to get an advantage in a situation: I think it’s time we played our ace, which is the fact that without us they wouldn’t be able to run this place.
This expression refers to card-playing. The ace usually has the highest value, and is associated with success.
See also: ace, play
Farlex Partner Idioms Dictionary
See also:
  • play your ace
  • wild card
  • a wild card
  • boom
  • ace in
  • ace in(to something)
  • stick that in your pipe and smoke it
  • put that in your pipe and smoke it
  • Put that in your pipe and smoke it!
  • have an ace in the hole