The Portland Timbers and D.C. United continued on their respective paths as the Timbers claimed a 2-0 victory at RFK Stadium to extend their unbeaten streak to 11 games.
United, meanwhile, is winless in its last 10 contests, and has earned just one point during that stretch.
Portland seized the advantage in the 21st minute from a throw in as Frederic Piquionne collected the ball in midfield and dribbled toward the penalty area.
He got to the edge of the box and laid a ball off for Rodney Wallace, who beat goalkeeper Bill Hamid with a shot from 10 yards at his near post.
The home side had a decent opportunity in the 51st minute when Kyle Porter arrived at the back post and headed just wide of the net.
But the Timbers doubled their advantage six minutes later with Ryan Johnson playing a nice ball over the top of the D.C. defense to Darlington Nagbe, who brought it down and drove a shot underneath Hamid.
The night was summed up for United in the 65th as Chris Pontius was left alone in front of goal, but he blazed a shot over the net from 10 yards.