Championship’s last ball finally breaks tie (5)
I believe the answer is:
title
'championship's' is the definition.
(synonyms)
'last ball finally breaks tie' is the wordplay.
'finally' indicates one should take the final letters.
'breaks' indicates putting letters inside.
The last letters of 'last ball' are 'tl'.
'tl' placed into 'tie' is 'TITLE'.
(Other definitions for title that I've seen before include "Name - legal right" , "established claim to ownership" , "Caption; name" , "Rank < deed" , "Right - name - rank" .)