Desert flag Mike brought back (5)
I believe the answer is:
merit
'desert' is the definition.
(I've seen this before)
'flag mike brought back' is the wordplay.
'flag' becomes 'tire' (both can mean to become weary).
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'brought back' shows that the letters should be reversed in order.
'tire'+'m'='tirem'
'tirem' reversed gives 'MERIT'.
(Other definitions for merit that I've seen before include "credit" , "distinction" , "Worth; deserve" , "Quality deserving reward" , "Have a right" .)