Osaka's first service returned in game (4)
I believe the answer is:
faro
'game' is the definition.
(I know that Faro is a type of card game)
'osaka's first service returned' is the wordplay.
'osaka's first' becomes 'o' (rst letter of 'osaka').
'service' becomes 'raf' (Royal Air Force).
'returned' says the letters should be written in reverse.
'o'+'raf'='oraf'
'oraf' written backwards gives 'FARO'.
'in' is the link.
(Other definitions for faro that I've seen before include "Card game - Portuguese resort" , "European port" , "Gambling game - Algarve capital" , "Portuguese city" , "Atlantic port" .)