Matteo Mancosu brace as Montreal Impact see off D.C. United

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.