Gag about parent sporting tie lacking originality (7)
I believe the answer is:
rematch
'sporting tie lacking originality' is the definition.
I can't tell whether this definition defines the answer.
'gag about parent' is the wordplay.
'gag' becomes 'retch' (I've seen this before).
'about' is an insertion indicator.
'parent' becomes 'ma' (ma can mean mum or mother).
'retch' enclosing 'ma' is 'REMATCH'.
Can you help me to learn more?
(Other definitions for rematch that I've seen before include "Later encounter" , "Return game" , "new bout" , "Teams' second game" , "Return fixture" .)