Liverpool’s two sides are so evenly matched? (5-5)
I believe the answer is:
fifty-fifty
'evenly matched?' is the definition.
(as in a fifty-fifty chance)
'liverpool's two' is the wordplay.
'liverpool's' becomes 'fifty' (I can't justify this - if you can you should believe this answer much more).
'two' shows that letters should be duplicated.
'fifty' duplicated is 'FIFTY-FIFTY'.
'sides are so' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for fifty-fifty that I've seen before include "Fairly" , "Evenly divided" , "Equally" , "Evens" .)