Midfielder Luciano Acosta scored the other two goals as DC United posted a crucial victory. DC goalkeeper Bill Hamid made six saves.

The win elevated DC United (8-11-6, 30 points) into a tie for seventh place in the Eastern Conference with the New England Revolution. DC stands six points behind the sixth-place Montreal, which currently holds the final playoff spot, but DC has three games in hand on the Impact.

Midfielder Jeff Larentowicz scored the lone goal for Atlanta United (16-5-6, 54 points), who remain one point behind the first-place New York Red Bulls in the East.

Atlanta star forward Josef Martinez failed to score, ending his streak of registering at least one goal in nine consecutive games. He matched the MLS record in that category -- held by Portland's Diego Valeri -- in Atlanta's last match when he set the MLS single-season record with his 28th goal of the season.

Rooney converted a penalty kick in the 52nd minute after midfielder Ezequiel Barco was called for a foul in the box against DC United's Paul Arriola.

Rooney lined up the shot, and Atlanta goalkeeper Brad Guzan guessed to his right. Rooney went the other direction with a low skidding shot into the net to give DC United a 2-1 edge.

Martinez had a solid opportunity to tie the score in the 67th minute after being set up by midfielder Miguel Almiron. However, his right-footed shot sailed wide left, and he came up empty on all three of his shots in the match.

The failure to convert was magnified in the 77th minute when Rooney was in the midfield and chipped a pass ahead to a streaking Acosta. Acosta raced in with only Larentowicz back to defend, and once he got inside the box, he sent a left-footed shot past Guzan to make it 3-1.

DC United went up 1-0 in the 29th minute as Hamid booted the ball up field and Rooney flicked a pass with his head. The ball reached Acosta, who worked around two defenders and sent a right-footed shot to the right of Guzan.

Barco took a corner kick in the 39th minute and sent it into the middle of the box. Larentowicz was in the right position and easily headed the ball past Hamid to even the score.

Atlanta United held a 22-9 edge in shots, including a 7-5 advantage in shots on target.