Queen's champion upset artificial intelligence (8)
I believe the answer is:
victoria
'queen's' is the definition.
(Queen Victoria)
'champion upset artificial intelligence' is the wordplay.
'champion' becomes 'victor' (I've seen this in another clue).
'upset' says the letters should be written backwards.
'artificial intelligence' becomes 'AI' (synonyms).
'ai' in reverse letter order is 'ia'.
'victor'+'ia'='VICTORIA'
(Other definitions for victoria that I've seen before include "Capital of the Seychelles" , "falls in > London station" , "Old carriage" , "Wood" , "one wasn't amused" .)