English after opening in ball game (9)
I believe the answer is:
bagatelle
'game' is the definition.
(I know that bagatelle is a type of table game)
'english after opening in ball' is the wordplay.
'english' becomes 'E' (abbreviation).
'after' means one lot of letters go next to another.
'opening' becomes 'gate' (a gate is an opening or entrance).
'in' is an insertion indicator.
'gate' placed into 'ball' is 'bagatell'.
'e' after 'bagatell' is 'BAGATELLE'.
(Other definitions for bagatelle that I've seen before include "no serious work" , "Board game - trifle" , "Something trifling and negligible" , "Board-game, trifle" , "Trifling matter" .)