Real Salt Lake became the first side to 10 wins this season with a 3-0 victory at Chivas USA.
Edgar Espindola netted either side of half-time for the Western Conference leaders, before Will Johnson added a third in the dying moments.
The Eastern Conference leaders were also victorious as Chris Pontius bagged the only goal for DC United 12 minutes from time in a 1-0 win at the Philadelphia Union.
They remained two points clear of Kansas City, who were 2-0 winners over Toronto FC. CJ Sapong after 18 minutes and Julio Cesar 16 minutes later got the goals.
Adam Moffat struck 14 minutes from time to give the Houston Dynamo a 2-1 win over Texas rivals FC Dallas, who played nearly half an hour with 10 men.
Will Bruin put Houston ahead after three minutes and, though Goncalves Jackson levelled just before the hour, the Dynamo were given a boost when Jair Benitez was dismissed in the 63rd minute - and Moffat took advantage.
The Montreal Impact were 4-1 winners over the Seattle Sounders, who paid for the 56th-minute dismissal of Jhon Hurtado.
The Impact were already 2-0 up at the time, through Felipe Martins and Justin Mapp, and they scored twice mroe though Andrew Wenger and Lamar Neagle. Eddie Johnson pulled one back in the 61st minute, making it 3-1 at the time.
The Vancouver Whitecaps overcame the dismissal of Darren Mattocks on the hour to beat the Colorado Rapids 1-0 thanks to a goal from Sebastien Le Toux 10 minutes from time, while the match between the New England Revolution and the Columbus Crew ended goalless.