Rest of the game? (3)
I believe the answer is:
I believe this clue is a double definition.
'rest' is the first definition.
(I know that nap is a type of sleep)
'the game' is the second definition.
(I've seen this before)
'of' acts as a link.
(Other definitions for nap that I've seen before include "Snatch forty winks" , "soft, fluffy surface" , "A brief snooze" , "Short sleep on soft surface texture?" , "Raised fibres on surface of cloth or leather" .)