a dab hand
Someone who is skilled in a particular area. Primarily heard in UK, Australia. Amanda can fix that hole in your blouse—she's a dab hand at sewing.
a dab hand
BRITISHCOMMON If you are a dab hand at something, you are very good at doing it. She was a dab hand at solving crossword puzzles. We gave big lunches every weekend and I became a dab hand at roasts. Note: In the late 17th century, `dab' meant clever or skilful.