Potion team in anger knocked back (6)
I believe the answer is:
elixir
'potion' is the definition.
(I know that elixir is a type of potion)
'team in anger knocked back' is the wordplay.
'team' becomes 'XI' (a football team, from Roman numerals for rr).
'in' means one lot of letters goes inside another.
'anger' becomes 'rile' (I've seen this before).
'knocked back' shows that the letters should be reversed in order.
'xi' put into 'rile' is 'rixile'.
'rixile' in reverse letter order is 'ELIXIR'.
(Other definitions for elixir that I've seen before include "Potion, panacea" , "Substance that alchemists believed could turn base metals into gold" , "Liquid supposed to prolong life in olden days" , "Invigorating drink" , "Magic drink believed to cure all ills" .)