The ones at Wimbledon? (7)
I believe the answer is:
singles
'the ones' is the definition.
('single' can be a synonym of 'one')
'at wimbledon?' is the wordplay.
I cannot quite understand how this works, but
'at' could be 'in' and 'in' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for singles that I've seen before include "Type of tennis match" , "Ones" , "Non-return tickets" , "Form of tennis" .)