Gonzalo Martinez's goal was enough for Atlanta to claim a fourth straight victory by beating Orlando City 1-0 in Georgia.
Former River Plate midfielder Martinez scored his first goal for the club in the 14th minute, brilliantly curling Hector Villalba's pass into the top corner.
Frank de Boer's men climbed into fifth in the Eastern Conference, six points behind the top two in Philadelphia Union and DC United.
DC joined Philadelphia on 23 points thanks to a 1-0 win over Sporting Kansas City at Audi Field.
Paul Arriola received Wayne Rooney's pass before curling an effort past Sporting goalkeeper Tim Melia from the edge of the area.