From Longman Dictionary of Contemporary Englishwork like a charmwork like a charmto work exactly as you had hoped The new sales program has worked like a charm. → charm
Examples from the Corpus
work like a charm• A slap on the hand or the behind works like a charm for one parent-child combination.• However, the schmaltzy parts, near the end, work like a charm.• But let me first applaud the coupling: it works like a charm.• This time, the setup worked like a charm.• Our new accounting system works like a charm. 