Crossword Genius

Number one, assess as excellent (5-4)

Ross

I believe the answer is:

first-rate

'excellent' is the definition.
(I've seen this before)

'number one assess' is the subsidiary indication.
'number one' becomes 'first' ('first' can be a synonym of 'number one').
'assess' becomes 'rate' (rating is a kind of assessing).
'first'+'rate'='firstrate'

'as' is the link.

(Other definitions for first-rate that I've seen before include "Top-class, excellent" , "Of the highest excellence" , "Stir after to be really excellent" , "Start fire to be really excellent" , "Prime" .)

I've seen this clue in the Evening Standard.
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