press (your) luck

See at: down on luck

• once in a lifetime
• once in a while
• once upon a time
• on cloud nine
• on coat-tails
• on course
• on cue
• on dangerous ground
• on deck
• on demand
• on doorstep
• on duty
• one after the other
• one and all
• one and the same
• on earth
• one day
• one-day wonder
• on edge
• one for the books
• one for the road
• One good turn deserves another.
• one-hit wonder
• one-horse race
• one-horse town