Put money on scrap, a fabulous contest (9)
I believe the answer is:
quidditch
'a fabulous contest' is the definition.
(magical game in the Harry Potter books)
'put money on scrap' is the wordplay.
I cannot quite understand how this works, but
'money' could be 'quid' and 'quid' is found within the answer.
'scrap' could be 'ditch' (I've seen this before) and 'ditch' is found within the answer.
No letters remain.
This explanation may well be incorrect...
(Other definitions for quidditch that I've seen before include "Harry Potter's game" , "Harry Potter aerial game" .)