One stroke put up a good score (3)
I believe the answer is:
par
'a good score' is the definition.
(I've seen this before)
'one stroke put up' is the wordplay.
'one stroke' becomes 'rap' (rap is a kind of stroke).
'put up' is a reversal indicator.
'rap' written backwards gives 'PAR'.
(Other definitions for par that I've seen before include "Standard number of strokes for a golf hole" , "Normal golfing score" , "Average standard" , "Median" , "level footing" .)