Origin of a Wimbledon favourite (4)
I believe the answer is:
seed
This clue is a double definition.
'origin' is the first definition.
(seed is a kind of origin)
'wimbledon favourite' is the second definition.
(tennis players are seeded)
'of a' acts as a link.
(Other definitions for seed that I've seen before include "one of the top players" , "Kernel" , "From which things grow" , "See 19" , "Court favourite" .)