Great produces a foul -- sub sent off (8)
I believe the answer is:
fabulous
'great' is the definition.
(I've seen this before)
'a foul sub sent off' is the wordplay.
'sent off' indicates an anagram.
'a'+'foul'+'sub'='afoulsub'
'afoulsub' with letters rearranged gives 'FABULOUS'.
'produces' acts as a link.
(Other definitions for fabulous that I've seen before include "almost incredible" , "Ace" , "Marvellous, incredibly great" , "Legendary or wonderful" , "Smashing" .)