Striking single, move faster than opponent (6)
I believe the answer is:
Here is my best explanation:
'move faster than opponent' is the definition.
'striking single' is the subsidiary indication.
'striking' becomes 'out' (striking out is a common phrase).
'single' becomes 'run' (cricket).
(Other definitions for outrun that I've seen before include "Go faster than, on the gallop", "Go faster than as in foot race", "Be too fast for on foot", "Overtake, escape" and "Lose".)