Organise heats in a rush (5)
I believe the answer is:
haste
'a rush' is the definition.
(I know that rush can be written as haste)
'organise heats' is the wordplay.
'organise' is an anagram indicator.
'heats' with letters rearranged gives 'HASTE'.
'in' acts as a link.
(Other definitions for haste that I've seen before include "Expedition" , "Hurry, urgency" , "Rush; urgency" , "Speediness or rush" , "Heats (anag.)" .)