Grip hard racket the wrong way on advantage to American (8)
I believe the answer is:
adhesion
'grip' is the definition.
(grip is something's adhesion to a surface)
'hard racket the wrong way on advantage to american' is the wordplay.
'hard' becomes 'h'.
'racket' becomes 'noise' (I've seen this before).
'the wrong way' is a reversal indicator.
'on' says to put letters next to each other.
'advantage to american' becomes 'ad' (US term for advantage in tennis).
'noise' in reverse letter order is 'esion'.
'h'+'esion'='hesion'
'hesion' put after 'ad' is 'ADHESION'.
(Other definitions for adhesion that I've seen before include "strong attachment" , "The property of sticking" , "Tackiness" , "He's no aid to sticker" , "Adonis, he may be a sticker" .)