From Longman Dictionary of Contemporary Englishcome/turn up trumpscome/turn up trumpsSUCCEED IN DOING somethingto provide what is needed, especially unexpectedly and at the last moment Paul came up trumps and managed to borrow a car for us. → trump
Examples from the Corpuscome/turn up trumps• Conrad Allen came up trumps again, finishing fourth in the boys 800 metres in a personal best 2 mins. 22.• Ibanez seem to have taken another daring step in their continuing success story and come up trumps once again.• And a dream come true ... The advert for grandparents that came up trumps.• In part two: Four of a kind ... Durnin plays the winning hand as United come up trumps against Luton.• You've come up trumps, Derek.