He may reward a 'zero blemish' performance (5)

I believe the answer is:

oscar

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'reward a zero blemish performance' is the definition.
'Oscar' can be an answer for 'reward' (thesaurus). I'm unsure of the 'a zero blemish performance' bit.

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for oscar that I've seen before include "Film award; --- Hammerstein" , "One of several given to Chicago" , "-- Wilde, author" , "Mr Wilde - film award" , "One close to Mike" .)

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