Club gets convict into hellish upset (10)
I believe the answer is:
shillelagh
'club' is the definition.
(shillelagh is a kind of club)
'convict into hellish upset' is the wordplay.
'convict' becomes 'lag' (I've seen this before).
'into' indicates putting letters inside.
'upset' indicates anagramming the letters.
'hellish' anagrammed gives 'shilleh'.
'lag' placed within 'shilleh' is 'SHILLELAGH'.
'gets' is the link.
(Other definitions for shillelagh that I've seen before include "Irish cudgel" , "Irish club" .)