Burning to sort out some of the also-rans (5)
I believe the answer is:
arson
'burning' is the definition.
(arson is a kind of burning)
'sort out some of the also-rans' is the wordplay.
'sort out' is an anagram indicator.
'some of' becomes 'o'.
'the also' means one lot of letters go next to another.
'o'+'rans'='orans'
'orans' with letters rearranged gives 'ARSON'.
'to' is the link.
(Other definitions for arson that I've seen before include "criminal fire-raising" , "Criminal burning of property" , "Malicious crime" , "A burning crime" , "matchplay, say?" .)