meet your Waterloo
From Longman Dictionary of Contemporary Englishmeet your Waterloomeet your WaterlooLOSE A GAME, COMPETITION, OR WARto finally be defeated after you have been successful for a long time → meetmeet your Waterloomeet your Waterlooto be finally defeated after a long period of success Despite widespread unpopularity, the party did not meet its Waterloo until the election of 1997. → Waterloo