Montreal's Bojan Krkic scored the tying goal in the 81st minute as the Impact held on to earn a 1-1 draw with visiting Atlanta United on Sunday afternoon.
However, the draw was not enough to keep the Impact's chances for the postseason alive. Montreal (38 points) needed wins in its final two games and two losses by New England to have any chance.
The Revolution cemented the seventh and final playoff spot with a 2-0 win Sunday against New York City FC.
Julian Gressel and Emerson Hyndman worked a beautiful give-and-go play inside the box to give Atlanta United a 1-0 lead in the 53rd minute that it carried into the stretch of the match. Gressel dribbled into the penalty area and passed to Hyndman, who quickly returned the ball to Gressel with a back heel.
From there, Montreal goalkeeper Clement Diop had no chance to stop Gressel's scoring kick, which came in the 53rd minute.
Atlanta United (55 points) remain in the running for the second-seed in the Eastern Conference. Atlanta is already guaranteed a home match in the upcoming MLS Cup playoff and can finish no worse than third in the conference.
The Impact's tying goal came with less than 10 minutes left when Krkic waited in the goal mouth for a centering pass from Orji Okwonkwo, who had carried the ball down the right sideline before turning the corner and finding Krkic in the clear for a right-footed tally.
Atlanta's Hector Villalba scored what would have been the winning tally three minutes later but after a video review, the goal was been called back for offside.
The sides played to a scoreless first half, although both had excellent chances to find the net.
Atlanta United's Brandon Vasquez ripped a shot from just outside the box in the 14th minute that Diop dove low and to his right to push away.