Assistant from place comic upset (10)
I believe the answer is:
accomplice
'assistant' is the definition.
(thesaurus)
'place comic upset' is the wordplay.
'upset' indicates an anagram.
'place'+'comic'='placecomic'
'placecomic' with letters rearranged gives 'ACCOMPLICE'.
'from' is the link.
(Other definitions for accomplice that I've seen before include "Partner in crime" , "Colleague" , "criminal partner" , "Partner in plan" , "ally" .)