Have ambition but it may damage you (3,4)

I believe the answer is:

own goal

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

I don't understand how the rest of the clue works.

(Other definitions for own goal that I've seen before include "Defender's faux pas" , "Act harming the perpetrator's interests" , "Costly footballing error" , "Self-damaging mistake" , "big mistake" .)

I've seen this clue in The Irish Times.

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