Atlanta United still has many games to play, including another on Saturday at Philadelphia, but if it gets deep into September and still hasn’t locked up a playoff spot it can only wonder what happened every time it played D.C. United.

For the third time this season, the Five Stripes were beaten by what is arguably the league’s worst team. On Wednesday, a 1-0 defeat came after an own goal by Michael Parkhurst in the 46th minute at RFK Stadium. It followed a 3-1 loss at Bobby Dodd Stadium on April 30, and a 2-1 loss on June 21 at RFK. Of D.C. United’s seven wins, three have come against Atlanta United. Of its 21 goals scored, six have come against Atlanta United.

With those now forever-lost nine points, Atlanta United would be well within the six-team playoff line and challenging NYCFC for second place in the East. Instead, Atlanta United (10-8-5) is stuck on 35 points and remains outside the playoffs in seventh with 35 points. It has played one fewer games than sixth-place Montreal and trails the Impact by one point.

The defeat snapped Atlanta United’s six-game unbeaten streak and makes Saturday’s game against the Union a must-win to keep pace with the teams it is chasing. Toronto, NYCFC and Chicago are virtual locks, leaving five teams chasing three spots.

D.C. United took a 1-0 lead on an own goal charged to Michael Parkhurst. Russell Canouse’s header went off Parkhurst’s thigh and in in the 47th minute. The play started with a well-taken shot by Canouse. Brad Guzan leaped to his left to keep the ball from sailing into the upper right corner. The deflection somehow rolled along the end line and stayed inbounds. Lloyd Sam ran onto it and hit a chip across the goal to Canouse, who headed it down and into the mouth of the goal.

Atlanta United fielded what is arguably its strongest offensive lineup, helped by the return of Josef Martinez and Greg Garza from injuries. Martinez, a striker made his seventh start and 10th appearance this season. He has missed the past three games because of a bruised right foot. Atlanta United went 1-0-2 in those games. He missed 10 consecutive games earlier this season because of a thigh injury sustained while playing for the Venezuelan national team. The team went 3-4-3 in that stretch. Garza returned from a shoulder injury suffered in the MLS All-Star game. It forced him to miss the 1-1 tie at Sporting KC.

After the opening 30 minutes, Atlanta United looked like a team that hadn’t played in two weeks. Short passes were put out of bounds. The few good crosses Atlanta United were put across the face of the goal where no one was waiting.

D.C. United did an excellent job of clogging the middle of the field and taking away any seams that Atlanta United could explot with passes through the lines for Martinez, Yamil Asad or Hector Villalba to run onto.

Gerardo Martino used his substitutions to try to spark the offense. Julian Gressel came on for fullback Anton Walkes and then Brandon Vazquez, who provided a boost late against Sporting KC, came on for Villalba.

Atlanta United’s best chance was its last, a cross that the sliding Martinez couldn’t turn into the tying goal, replacatinng the magic of Joseph Peterson, who scored late to tie Sporting KC 1-1,  or Villalba’s theatrics with tying goal against Orlando City at Bobby Dodd, and the late winner at Orlando City.