Ordinary against Australia – turned up exhausted (7)
I believe the answer is:
vanilla
'ordinary' is the definition.
(vanilla can mean ordinary or conventional)
'against australia turned up exhausted' is the wordplay.
'against' becomes 'v' (abbreviation for 'versus').
'australia' becomes 'A' (abbreviation for Australia).
'turned up' says the letters should be written backwards.
'exhausted' becomes 'all in' ('all in' can mean exhausted).
'allin' reversed gives 'nilla'.
'v'+'a'+'nilla'='VANILLA'
(Other definitions for vanilla that I've seen before include "lacking any special features" , "Flavouring from pod of certain orchids" , "Bland" , "devoid of special features" , "Tasty flavouring for ice-cream" .)