Upset quieter children in further confrontation (7)
I believe the answer is:
rematch
'further confrontation' is the definition.
The definition suggests a singular noun which matches the answer.
'upset quieter children' is the wordplay.
'upset' says the letters should be written in reverse.
'quieter' becomes 'tamer' ('tame' is associated in meaning with 'quiet').
'children' becomes 'ch' (genealogical abbreviation).
'tamer' reversed gives 'remat'.
'remat'+'ch'='REMATCH'
'in' is the link.
Can you help me to learn more?
(Other definitions for rematch that I've seen before include "new bout" , "Return fixture" , "Further engagement of the same contestants" , "Another game" , "Teams' second game" .)