Obtain excellent start (3,8)

I believe the answer is:

get cracking

'start' is the definition.
(to get cracking is to start or begin)

'obtain excellent' is the wordplay.
'obtain' becomes 'get' (synonyms).
'excellent' becomes 'cracking' (cracking can mean excellent or brilliant).
'get'+'cracking'='GET CRACKING'

(Other definitions for get cracking that I've seen before include "Bestir oneself" , "Start moving quickly" , "Act quickly and decisively" , "start flying" , "Start something at once" .)

I've seen this clue in The Times.

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