Ali, knocked out in fight, needs rescue (4,3)
I believe the answer is:
bail out
'rescue' is the definition.
(I've seen this before)
'ali knocked out in fight' is the wordplay.
'knocked out' indicates anagramming the letters (I've seen this in other clues).
'in' means one lot of letters goes inside another.
'fight' becomes 'bout' (as in a bout in boxing).
'ali' with letters rearranged gives 'ail'.
'ail' inserted inside 'bout' is 'BAIL OUT'.
'needs' acts as a link.
(Other definitions for bail out that I've seen before include "Rescue from tight spot" , "escape from aircraft" , "Provide support" , "Rescue from trouble" , "Withdraw" .)