Tennis champ Osaka (5)
I believe the answer is:
'tennis champ osaka' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for naomi that I've seen before include "-- Campbell, British model" , "Mother-in-law of Ruth (Bible)" , "Ruth's mother-in-law (Bible)" , "Girl's name -- I moan (anag)" , "Girl" .)