Help Ballesteros carrying putter at last (5)
I believe the answer is:
serve
'help' is the definition.
(I know that help can be written as serve)
'ballesteros carrying putter at last' is the wordplay.
'ballesteros' becomes 'seve' (golfer Seve Ballesteros).
'carrying' is an insertion indicator.
'at last' suggests the final letters.
The last letter of 'putter' is 'r'.
'seve' enclosing 'r' is 'SERVE'.
(Other definitions for serve that I've seen before include "get game started" , "Begin a tennis game" , "Hand out, food or drink say" , "Help" , "Distribute" .)