Offspring of top player (4)
I believe the answer is:
seed
This clue is a double definition.
'offspring' is the first definition.
(I've seen this before)
'top player' is the second definition.
(eg a seeded tennis player)
'of' is the link.
(Other definitions for seed that I've seen before include "one of the best players" , "one of the top players" , "What is sown" , "Race" , "offspring" .)