A villain tailed by Sherlock, ultimately for sport (7)

'sport' is the definition.
(Asian contact sport)

'a villain tailed by sherlock ultimately' is the wordplay.
'a villain' becomes 'baddie' (a bad character in a story).
'tailed' means to remove the last letter (to tail something can mean to remove its end).
'by' means one lot of letters go next to another.
'sherlock ultimately' becomes 'ka' (I can't justify this - if you can you should believe this answer much more).
'baddie' with its final letter taken away is 'baddi'.
'baddi' after 'ka' is 'KABADDI'.

'for' is the link.