When pro is beaten for title (9)
I believe the answer is:
ownership
'for title' is the definition.
(legal term for ownership)
'when pro is beaten' is the wordplay.
'beaten' indicates anagramming the letters (letters beaten up or destroyed).
'when'+'pro'+'is'='whenprois'
'whenprois' anagrammed gives 'OWNERSHIP'.
(Other definitions for ownership that I've seen before include "Proprietorship, possession" , "Legal title" , "The right of possessing something" , "Proprietary right of possession" .)