Contestant used Iraqi fuel (9)
I believe the answer is:
qualifier
'contestant' is the definition.
(I know that qualifier is a type of contestant)
'used iraqi fuel' is the wordplay.
'used' is an anagram indicator.
'iraqi'+'fuel'='iraqifuel'
'iraqifuel' with letters rearranged gives 'QUALIFIER'.
(Other definitions for qualifier that I've seen before include "heat" , "Contestant who meets the basic requirements" .)