Record past Yankee breakthrough (9)

I believe the answer is:

discovery

'breakthrough' is the definition.
(I know that breakthrough can be written as discovery)

'record past yankee' is the wordplay.
'record' becomes 'disc' (eg a CD, compact disc).
'past' becomes 'over' (both can mean finished).
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'disc'+'over'+'y'='DISCOVERY'

(Other definitions for discovery that I've seen before include "Bay in southeast Australia" , "Process of finding" , "Find - Scott's ship" , "Breakthrough" , "old ship" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app