Tesho Akindele blasted in the go-ahead goal in the 86th minute and FC Dallas rallied for a 2-1 victory over the Galaxy on Saturday night.
Mauro Diaz, who assisted on both goals, set up Akindele with a diagonal cross from near midfield as the Galaxy's five-game unbeaten streak came to an end.
Blas Perez pulled FC Dallas (6-2-2) even in the 77th minute, slipping past goalkeeper Jaime Penedo for an open-net finish. Diaz floated a chip pass over the Galaxy defense to create the space for Perez.
FC Dallas remained first in the overall MLS standings, tied with the Vancouver Whitecaps.
Gyasi Zardes scored the only goal for the Galaxy (3-3-5) in the 59th minute, redirecting Stefan Ishizaki's corner kick with a header.