Dilettante in a beaten RU team (7)
I believe the answer is:
amateur
'dilettante' is the definition.
(I've seen this in another clue)
'a beaten ru team' is the wordplay.
'beaten' indicates an anagram (letters beaten up or destroyed).
'ru'+'team'='ruteam'
'ruteam' is an anagram of 'mateur'.
'a'+'mateur'='AMATEUR'
'in' acts as a link.
(Other definitions for amateur that I've seen before include "I'm no expert!" , "Layperson" , "One who pursues an activity as a pastime only" , "Layman" , "Non professional, eight across" .)