Contest fewer in number, being unbeatable (9)
I believe the answer is:
matchless
'unbeatable' is the definition.
(I've seen this before)
'contest fewer in number' is the wordplay.
'contest' becomes 'match' (match is a kind of contest).
'fewer in number' becomes 'less' (I've seen this before).
'match'+'less'='MATCHLESS'
'being' is the link.
(Other definitions for matchless that I've seen before include "Having no equal" , "Unequalled" , "reason for rubbing sticks together?" , "Unrivalled" , "Unbeatable" .)