A cry for help about defeat - it needs careful handling (8)
I believe the answer is:
asbestos
'it needs careful handling' is the definition.
The definition suggests a singular noun which matches the answer.
'a cry for help about defeat' is the wordplay.
'cry for help' becomes 'sos' (an SOS message sent in an emergency).
'about' is an insertion indicator.
'defeat' becomes 'best' (besting is a kind of defeating).
'sos' going around 'best' is 'sbestos'.
'a'+'sbestos'='ASBESTOS'
Can you help me to learn more?
(Other definitions for asbestos that I've seen before include "condemned building material" , "Fire-retardant material" , "retardant" , "Fireproof material, now known to be dangerous" , "Insulating mineral" .)