From Longman Dictionary of Contemporary Englishpurple patchpurple patcha time when you are very successful – used especially in news reports Steve’s purple patch continued with a second victory on Tuesday. → purple
Examples from the Corpus
purple patch• Ian and a friend bagged 90 cod in just two hours in one purple patch.• Were they a coincidence or are you going through a purple patch at the moment?• Talk of his absence coinciding with our recent purple patch can't have helped.• A 15-minute purple patch in which they scored 19 points a 22-14 win Durham City.• It is neither a purple patch nor is it coincidence.• There are very few purple patches whereas the outdoor game - tactically - can be slow. 