Supporter giving Wimbledon heart, for instance (3)
I believe the answer is:
leg
'supporter' is the definition.
'giving wimbledon heart for instance' is the wordplay.
'giving' is a charade indicator (letters next to each other).
'heart' indicates the central letters.
'for instance' becomes 'eg' ('e.g.' can be a synonym of 'for instance').
The centre of 'wimbledon' is 'l'.
'l'+'eg' is 'LEG'.
(Other definitions for leg that I've seen before include "Run < on" , "Lower limb" , "Support; cricket side" , "Limb; stage" , "Gigot" .)