give credit where it's due.

give credit where it's due (to acknowledge someone's contribution or ability) — признать, отметить чьи-л. заслуги

Give credit where credit is due. {Prov.} — Всегда воздавай по заслугам.

Jill: Jane, that was a wonderful meal.
Jane: I must give credit where credit is due; Alan helped with all of the cooking.
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Ellen: Roger is pompous, petty, and immature. I think he's completely worthless. Jane: Now, Ellen, give credit where credit is due; he's also extremely smart.(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

————

-dustman Dulittle-
'Well, I never thought she'd clean up so good-looking.
She does me credit, don't she, governor?'

-colonel Pickering -
'All alone you hurdled every obstacle in sight'
-professor Higgins -
Now wait, now wait Give credit where it's due
A lot of the glory goes to you '

(from 'My fair lady)'