a treat

(do something) a treat

To do something very well, adeptly, or satisfactorily. Primarily heard in UK. After we oiled up the chain a bit, that old bike worked a treat. My daughter's singing went down a treat with the family members gathered at our house for Christmas. Wow, this suit fits a treat! It makes such a difference going to a tailor.
See also: treat

— a treat

used to indicate that someone or something does something specified very well or satisfactorily. British informal
1988 Ray Pickernell Yanto's Summer A flared cream pleated skirt that complemented those long perfect brown legs, and a powder blue tee shirt that matched her eyes a treat.
See also: treat