Does he maintain he should be champ? (9)
I believe the answer is:
contender
'champ?' is the definition.
(champ is a kind of contender)
'does he maintain he' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'der' and 'der' is present in the answer.
This may be the basis of clue (or it may be nonsense).
'should be' is the link.
Can you help me to learn more?
(Other definitions for contender that I've seen before include "One striving" , "No red cent (anag.)" , "Struggler in rivalry" , "Candidate" , "One who strives" .)