Concerning lighter return game (7)
I believe the answer is:
rematch
'return game' is the definition.
(I've seen this before)
'concerning lighter' is the wordplay.
'concerning' becomes 're' (both can mean on a particular topic).
'lighter' becomes 'match' (match is a kind of lighter).
're'+'match'='REMATCH'
(Other definitions for rematch that I've seen before include "Another game" , "Return fixture" , "new bout" , "Later encounter" , "Teams' second game" .)