The Montreal Impact stayed first in the East standings after a 1-1 draw with the Philadelphia Union on Saturday.
In a battle between the conference's surprise top two teams, Didier Drogba needed only three minutes before opening the scoring for Montreal.
Marco Donadel's corner was headed by C.J. Sapong straight to Drogba at the edge of the penalty area. He took one touch and blasted a shot just under the bar for his fourth goal in seven games this season.
The Union answered in the 24th minute as Laurent Ciman's slip allowed Chris Pontius to cross from the left side to an unmarked Sebastien Le Toux to feed Sapong in front for a tap-in.