Two score in Rome we hear and do better (5)

I believe the answer is:

excel

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

I don't understand the rest of the clue.

(Other definitions for excel that I've seen before include "Do really well, outshine others" , "Be highly proficient" , "Every one" , "Surpass; shine" , "well above average" .)

I've seen this clue in The Globe and Mail.

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