What's the chances of veterans eliminating rat? (5)

I believe the answer is:

evens

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'what's the chances' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for evens that I've seen before include "Half a chance" , "1-1" , "50-50 odds" , "Odds on something very likely to win" , "Smooths the odds" .)

I've seen this clue in the Irish Times (Crosaire) and the Irish Times.

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