To crash a car within a mile is phenomenal! (7)
I believe the answer is:
miracle
'is phenomenal' is the definition.
(I know that miracle is phenomenal)
'to crash a car within a mile' is the wordplay.
'to crash' indicates an anagram.
'within' indicates putting letters inside.
'car' is an anagram of 'rac'.
'rac' going within 'mile' is 'MIRACLE'.
(Other definitions for miracle that I've seen before include "Reclaim (anag) - supernatural act" , "It's said to happen by the divine intervention" , "Remarkable occurrence" , "Amazing or unexplained occurrence" , "Supernatural act of God" .)