What ace is in lap literally, an all-time champion? (6-7)

I believe the answer is:

record-breaker

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'champion?' is the definition.
(I know that record-breaker is a type of champion)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for record-breaker that I've seen before include "Best-ever performance achiever" , "Person having surpassed the previous best" .)

I've seen this clue in The Times.

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