The Colorado Rapids condemned the Columbus Crew to a heartbreaking defeat on penalties as they booked their place in the Eastern Conference final against the San Jose Earthquakes.
Leading 1-0 from the first leg, the Rapids needed an 84th-minute goal from Conor Casey to take the game to extra-time after strikes from Eddie Gaven and Robbie Rogers had made it 2-0 to Columbus on the night and 2-1 on aggregate.
All the penalty takers in the shoot-out were successful until Brian Carroll sent the tenth spot-kick high over the bar.
FC Dallas made it through to the Western Conference final with a 3-2 aggregate win over Real Salt Lake.
Leading 2-1 from the home leg, Dallas increased their lead after 17 minutes courtesy of Dax McCarty and, even though substitute Robbie Findley levelled it at 1-1 on the night with ten minutes to play, it was not enough.
Dallas will face either the Los Angeles Galaxy or the Seattle Sounders in the final.