Didier Drogba scored his fifth MLS goal to lead the Montreal Impact to a hard-fought 2-1 win over lowly Chicago Fire on Thursday  (AEST).

Former Chelsea striker Drogba netted the controversial 39th-minute opener at Stade Saputo in Montreal as Impact consolidated the sixth and final playoff spot in the Eastern Conference.

Drogba, who bagged a hat trick against Chicagp Fire just under three weeks ago and scored in last week's 3-0 win at home against the New England Revolution, wrestled Jeff Larentowicz to the ground and headed past Fire goalkeeper Jon Busch six minutes before halftime.

Fire - six points adrift at the bottom of the East after four consecutive defeats - drew level five minutes into the second half via David Accam, who bundled the ball over the line.

Montreal, however, was not to be denied a fifth straight game without defeat after Andres Romero tucked the ball beyond the onrushing Busch.

Impact defender Laurent Ciman, though, was sent off for a second bookable offence in the first minute of injury time, a blight on an otherwise perfect day for the home team.

Impact is sixth in the East on 39 points from 28 matches with six rounds remaining, four points clear of Orlando City, while the cellar-dwelling Fire remains well off the pace.

Thursday's (AEST) only other match saw the 10-man Houston Dynamo edge Sporting Kansas City 1-0.

Will Bruin's 67th-minute goal was enough for Dynamo to snap a run of back-to-back defeats, despite Boniek Garcia's red card three minutes later in Houston.

Dynamo is eighth in the Western Conference on 38 points, six points adrift of fifth-placed Sporting KC.