Sweetheart holds up item that helps swingers raise their game (3)
I believe the answer is:
tee
'item that helps swingers raise their game' is the definition.
(golf tee - golfers swing their clubs)
'sweetheart holds up' is the wordplay.
'holds' says the answer is hidden in the clue.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'eet' is hidden within 'sweetheart'.
'eet' written backwards gives 'TEE'.
(Other definitions for tee that I've seen before include "Golfing item" , "Starting place on the golf course" , "Where a hole starts" , "Golfer drives from it" , "Golfer's support" .)