Master a field sport in bad faith according to the Romans (4,4)

I believe the answer is:

mala fide

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'bad faith according to the romans' is the definition.
I can't tell whether this defines the answer.

'master a field sport' is the wordplay.
'master' becomes 'ma' (Master of Arts).
'sport' is an anagram indicator.
'a'+'field'='afield'
'afield' anagrammed gives 'lafide'.
'ma'+'lafide'='MALA FIDE'

'in' is the link.

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I've seen this clue in The Irish Times.

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