Dull players finished first (8)
I believe the answer is:
'dull' is the definition.
(I've seen this before)
'players finished first' is the wordplay.
'players' becomes 'cast' (I've seen this before).
'finished' becomes 'over' (similar in meaning).
'first' means one lot of letters go next to another.
'cast' after 'over' is 'OVERCAST'.
(Other definitions for overcast that I've seen before include "State of the sky when it is covered by clouds" , "not entirely fair" , "Of sky, covered with cloud" , "Cloud-covered" , "Gloomy like cloudy sky" .)