Fabian Castillo scored in the winner in 88th minute and FC Dallas clinched a playoff berth, beating the Los Angeles Galaxy 2-1 on Sunday night.
Galaxy goalkeeper Jaime Penedo errantly punched a dangerous cross directly out to Castillo, who headed it right back into the goal from the middle of the box.
David Texeira tied it for FC Dallas (15-11-6) with a one-timer in the 52nd minute, cutting behind two Galaxy defenders as Andres Escobar sent a perfectly weighted ball forward.
Stefan Ishizaki chipped over goalkeeper Chris Seitz into the side netting to open the scoring for the Galaxy (17-6-9) in the 22nd minute.
The Galaxy missed an opportunity to move ahead of the Western Conference rival Seattle Sounders for the MLS top spot. The clubs will finish the season with a home-and-home series to determine the Supporters' Shield winner.