Dallas is the only unbeaten team remaining in MLS after a win on Sunday (AEST), while Montreal Impact staged a superb comeback.

A 77th-minute goal from Maynor Figueroa saw Dallas end Sporting Kansas City's undefeated start to the season with a 1-0 win.

The former Wigan Athletic and Hull City defender headed in a clipped Michael Barrios cross at the back post as Dallas made it four wins in six games this season.

Oscar Pareja's men are second in the Western Conference, which is topped by Portland Timbers.

Portland continued its strong start to the season with a 2-1 win at home to Vancouver Whitecaps.

Darlington Nagbe opened the scoring for Timbers with a tremendous goal, skipping past two markers before his 20-yard effort went in off the crossbar in the 18th minute.

Darren Mattocks doubled the hosts' lead and they claimed all three points despite Fredy Montero's goal just before the hour mark, the forward putting away a rebound after his penalty was saved.

Montreal Impact produced a stunning comeback to deny Philadelphia Union its first win as the two teams played out a 3-3 draw.

A first-half brace from Roland Alberg either side of a C.J. Sapong goal had Union in control.

Ignacio Piatti pulled a goal back for Montreal prior to the break before a double from Anthony Jackson-Hamel secured a point for Impact.

New York Red Bulls continued its decent start to the campaign with a 2-0 win over Eastern Conference leader Columbus Crew, while Atlanta United beat Real Salt Lake 3-1.

Houston Dynamo claimed a 2-0 win over San Jose Earthquakes and New England Revolution played out a 2-2 draw against DC United.