Come up/turn up trumps
Definition 1 of 1
Pro Tip 1/3Unexpected Success
Use it when someone succeeds in a way that is surprising or unforeseen. 
Everyone doubted her, but she came up trumps with the best presentation.
Pro Tip 2/3Positive Outcome
It implies that the outcome was positive, usually better than what others anticipated. 
The underdog team turned up trumps in the championship game.
Pro Tip 3/3Versatile Phrase
Can be used in formal and informal situations alike, but is more common in casual speech. 
Our makeshift solution really came up trumps!