Message received, Mr Federer (5)

I believe the answer is:

roger

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'message received' is the definition.
(I've seen this in another clue)

'mr federer' is the wordplay.
'mr' becomes 'Rog'.
'federer' becomes 'er' (I can't justify this - if you can you should believe this answer much more).
'rog'+'er'='ROGER'

Can you help me to learn more?

(Other definitions for roger that I've seen before include "man, > I understand" , "Boy's name - received and understood" , "I've got the message" , "Boy - received and understood" , "... guy" .)

I've seen this clue in the Sydney Morning Herald.

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