David Villa helped New York City end the Chicago Fire's unbeaten run in MLS, while Dallas went top of the Western Conference.
Villa struck early in the second half as a 10-man City recorded a 2-1 win over the Fire on Saturday.
Yangel Herrera was sent off in the 12th minute at Yankee Stadium after a rash challenge on Fire star Bastian Schweinsteiger.
But Villa volleyed in the opener just after halftime before Frederic Brillant headed in the home side's second.
David Accam scored from 25 yards for Chicago, but they were unable to find another as their 11-match unbeaten league run was ended.
The win kept City in third but moved them to within a point of the Fire, who are two adrift of Toronto after the Eastern Conference leader drew 1-1 with the Colorado Rapids.
In the Western Conference, Dallas are top after a come-from-behind 2-1 win over the Montreal Impact.
A Michael Salazar header had given Montreal a 23rd-minute lead, but Cristian Colman delivered after the break for Dallas.
Colman tapped in an equalizer and his superb control and finish secured the three points just after the hour-mark.
Dallas is a point clear of Sporting Kansas City, who played out a third straight draw with a 1-1 result at Real Salt Lake.
The third-placed Houston Dynamo made a strong start before claiming a 3-1 victory against struggling DC United.
The LA Galaxy lost a thriller at New England as Teal Bunbury scored a brace to help the Revolution to a 4-3 win.
The New York Red Bulls were too good for Minnesota United 3-0 and the Columbus Crew edged the Philadelphia Union 1-0.