Atlanta United advanced to the MLS Cup in its second season despite a 1-0 loss to the New York Red Bulls in the second leg of the Eastern Conference final on Thursday in Harrison, N.J.
United won the two-legged series 3-1 on aggregate after a 3-0 victory at home on Sunday.
Tim Parker scored in the fourth minute of second-half stoppage time for the Red Bulls, but it was too late to mount a comeback in earnest.
Atlanta will host the Portland Timbers for the league championship on Dec. 8. The match will be the last as United's head coach for Argentine Gerardo "Tata" Martino, who is expected to be named Mexico's national team coach. Portland edged Sporting Kansas City 3-2 on Thursday to win the Western Conference final by the same score.
For the second time in the series, the Red Bulls had a goal overturned after video review. In the 80th minute, Aaron Long was ruled to have fouled goalkeeper Brad Guzan while heading in a shot.
Guzan made five saves, while New York's Luis Robles had four.
The Red Bulls set the MLS regular-season record for points (71), two points ahead of Atlanta, and were trying to reach the championship match 10 years after losing to the Columbus Crew 3-1 in their lone MLS Cup appearance.
New York could not allow Atlanta to score an away goal because it meant the Red Bulls would need four goals just to send the series to extra time.
That strategy almost went for naught in the first 15 seconds when Atlanta's Josef Martinez, who set the MLS record with 31 regular-season goals and added three more in the playoffs, had a prime opportunity from the center of the box that Robles saved.
Despite the desperate situation, the Red Bulls managed just one shot on goal in the first half, a low strike by Kaku in the 20th minute.
Atlanta now awaits the winner of the Western Conference final between Sporting Kansas City and the Portland Timbers, with the teams tied 0-0 after the first leg.