Andrew Wenger headed in a goal just before halftime and Felipe Martins added another for the Montreal Impact in a 2-0 victory over the Philadelphia Union at Saputo Stadium.
The Impact (9-13-3), who are 8-3-2 at home, opened a seven-point lead on eighth-place Philadelphia (7-11-2) in the Eastern conference, although the Union hold five games in hand.
Both clubs played the final 21 minutes with 10 men after Montreal's Nelson Rivas and forward Jack McInerney were shown red cards after a shoving match.
The Impact's win avenged a 2-1 loss in Philadelphia on July 14 on a Carlos Valdes goal in stoppage time. It was Montreal's second victory in a row after a 3-1 decision over New York a week earlier.