Does one thwarting goal make good relationship material? (6)

I believe the answer is:

keeper

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'one thwarting goal make good relationship material?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

I can't explain the rest of the clue.

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(Other definitions for keeper that I've seen before include "Football or cricket player" , "Custodian; bar across magnet" , "penalties will come my way" , "man at zoo" , "Zoo or park manager" .)

I've seen this clue in The Irish Times.

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