The Montreal Impact ran D.C. United off the field to advance to the MLS Cup Eastern Conference semifinals, beating Ben Olsen's team 4-2 at RFK Stadium in Washington, D.C.
Laurent Ciman put the visitors in front in the fourth minute from a corner kick, side-footing a volley past D.C. goalkeeper Bill Hamid for his first-ever MLS playoff goal.
Montreal continued on the front foot and had two decent chances, with Matteo Mancosu firing just wide of the left post, before his well-hit shot went right at Hamid minutes later.
And the Impact would find a second goal just before half-time as Ignacio Piatti played a lovely ball in from the left-wing, splitting four United defenders to allow Mancosu to redirect home from close range.
With D.C. pushing to cut into the Montreal lead, Mancosu delivered a death blow for the hosts when he headed home at the near post from a great ball in by Ambroise Oyongo.
United almost found its opener on the counter minutes later, Rob Vincent latching onto a Lamar Neagle through ball on the counter and beating Evan Bush only to fire into the side netting.
And Piatti would seal the deal as full-time approached, working a two-versus-one break with Mancosu and firing home for a 4-0 lead.
Neagle's 90th-minute headed goal for D.C. and an incredible long-range strike from Taylor Kemp were all-but meaningless except to improve the final scoreline.
Montreal advances to face the first-place New York Red Bulls in the Eastern Conference semifinals.