ace up (one's) sleeve

A secret advantage. My stamina is the ace up my sleeve for this race—the other runners don't stand a chance! The defense attorney waited for just the right time to play the ace up her sleeve—a new eye-witness.

Common Names:

Name	Pronounced	Usage
Javaid	-	Urdu
Abidan	ə-BIE-dən (English), AB-i-dan (English)	Biblical, Biblical Latin, Biblical Greek
Denton	DEN-tən	English
Ingomar	-	German, Ancient Germanic
Downs	[daunz]
Bernard	bər-NAHRD (English), BUR-nərd (English), ber-NAHR (French), BER-nahrt (Polish, Croatian)	English, French, Dutch, Polish, Croatian, Slovene, Czech, Ancient Germanic