Bradley Wright-Phillips scored two minutes into second-half injury time and the New York Red Bulls beat D.C. United 1-0 on Sunday to advance to the MLS Eastern Conference finals.
The Red Bulls, who won the first leg of the two-game series 1-0 last week in Washington, advanced on aggregate goals 2-0, marking the second straight year they have beaten their I-95 rivals in the semifinals.
The goal came on Wright-Phillips' second chance within minutes as D.C. United pushed forward needing a goal to force extra time.
Walker Zimmerman forced extra time with a 91st-minute goal and scored the clinching penalty kick to help top-seeded FC Dallas reach the MLS Cup Western Conference finals with victory Sunday night over the Seattle Sounders in their two-game series.
FC Dallas won 4-2 on penalty kicks after three lead-changing goals in the final 10 minutes of regulation time and 30 scoreless minutes of extra time.
The result after first the 180 minutes of the two-leg series were ties in both the aggregate score (3-3) and away goals (1-1).
The fourth-seeded Sounders, having won the first leg 2-1, tightened their defense to hold the series edge for the first 83 scoreless minutes.
Tesho Akindele broke through in the 84th, heading home Je-Vaughn Watson's cross.
The 2-2 aggregate score would have been enough for FC Dallas with the away goals tiebreaker, but the Sounders tied the game and took back the series lead when Chad Marshall headed in Marco Pappa's corner in the 90th.
Less than a minute later, Walker Zimmerman made it 2-1 for FC Dallas with a turnaround header which forced the two 15-minute, extra-time periods.
Kei Kamara scored his second goal of the match in extra time to give the Columbus Crew a 3-1 victory over the Montreal Impact to advance to face New York in the semifinals.
The Crew won the home-and-home series by a final aggregate score of 4-3.
The Montreal loss ends an amazing run for the Impact spurred on in part by the arrival of Didier Drogba to the club over the summer.
Ethan Finley hit a crucial goal in the 78th minute to force the game into extra time, where Kamara provided the heroics in front of the home crowd.
The Crew and Red Bulls will play the first leg for the finals in Columbus, Ohio on Nov. 22 and the second leg in Harrison, New Jersey on Nov. 29.
Meanwhile in Vancouver, Fanendo Adi scored off a feed from Diego Valeri in the 31st minute and Diego Chara added the capper in second-half stoppage time, sending Portland past Vancouver and to the MLS Western Conference finals for the second time in franchise history.
Portland, the No. 3 seed in the West, played to a 0-0 draw in the first-leg of the two-game series at home against Vancouver and got the critical road goal after withstanding an early rush from the Whitecaps. Portland will face FC Dallas in the Western Conference finals, with the first leg Nov. 22 in Portland.