Los Angeles Galaxy remains seven points ahead of the Seattle Sounders at the top of the MLS Western Conference after both sides won 3-0 on Saturday.
Mike Magee scored twice and Robbie Keane also found the target as the Galaxy enjoyed a comfortable win over the Vancouver Whitecaps.
And Seattle was a similarly easy winner over DC United thanks to a double from Alvaro Fernandez after Michael Fucito had opened the scoring.
In the Eastern Conference, the top two sides both went down to 1-0 defeats away from home.
Leader the Columbus Crew was beaten by the Philadelphia Union thanks to Sebastien Le Toux's 32nd-minute goal, while Sporting Kansas City failed to take advantage as it lost to Real Salt Lake, Nat Borchers scoring the only goal.
Elsewhere, Chicago Fire beat Chivas USA 3-2 despite playing more than 50 minutes with 10 men.
Chicago led 2-0 through goals from Cory Gibbs (two) and a Juan Pablo Angel own goal (26) before Gibbs was sent off eight minutes before the interval.
Chivas drew level with two goals in two minutes from Angel and Nick LaBrocca, but the home side snatched an unlikely winner five minutes from time through Dominic Oduro.
Toronto FC is three points clear of the bottom of the Eastern Conference after beating the Colorado Rapids 2-1.
Danny Koevermans scored twice in eight second-half minutes and Sanna Nyassi's reply on 69 minutes proved to be just a consolation.
Elsewhere, New York Red Bulls won 1-0 at FC Dallas courtesy of a Luke Rodgers strike on 36 minutes, while the Houston Dynamo beat the San Jose Earthquakes 2-1.
San Jose took the lead through Khari Stephenson (40) but Brad Davis (46) equalised from the penalty spot and Will Bruin (79) scored the winner just five minutes after coming on as a substitute.
