Defeat provided by one caught showing great joy (8)
I believe the answer is:
beatific
'showing great joy' is the definition.
(beatific means showing great joy or bliss)
'defeat provided by one caught' is the wordplay.
'defeat' becomes 'beat' (beating is a kind of defeating).
'provided by' becomes 'ifi' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'one caught' becomes 'c' (cricket abbreviation).
'beat'+'ifi'+'c'='BEATIFIC'
(Other definitions for beatific that I've seen before include "supremely happy" , "Angelic, saintly" , "Joyful" , "Feeling or expressing blissful happiness" , "Showing great happiness, perhaps a smile" .)