meet one's Waterloo

To experience a final and resounding defeat. (Napoleon Bonaparte suffered his crushing final defeat at the Battle of Waterloo.) The underdog team met their Waterloo in the championship game and lost to the best team in the league 17-1.

Suffer a major defeat, as in Our team's done well this season but is about to meet its Waterloo. This term alludes to Napoleon's defeat at Waterloo, Belgium, in 1815, marking the end of his military domination of Europe. It was being transferred to other kinds of defeat by the mid-1800s.

To experience a major defeat. Alluding to the final defeat of Napoleon at Waterloo in 1815, Wendell Phillips used the term in1859 to describe the defeat of abolitionist John Brown in organizing a slave uprising at Harpers Ferry, Virginia (“Every man meets his Waterloo at last”).