State capital of South Australia (8)
I believe the answer is:
adelaide
'state capital of south australia' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for adelaide that I've seen before include "Australian location" , "Lead aide out to Australia" , "somewhere in Australia" , "Queen to William IV - setting for many an 6 test" , "port in Oz" .)