Chad Barrett scored the only goal from a David Beckham free-kick as the Los Angeles Galaxy defeated Chivas USA 1-0 in the SuperClasico at the Home Depot Center.
Barrett scored in the 26th minute, the striker being left unmarked to head Beckham's delivery past goalkeeper Dan Kennedy for his third goal of the year. Beckham's sixth assist put him level with Houston's Brad Davis for the league lead.
The result sees the Galaxy extend their lead at the top of the Western Conference to six points.
Jeff Parke scored his first MLS goal in seven years, heading home a Tyson Wahl corner in stoppage time to give Seattle an unexpected 1-0 win over Sporting Kansas City.
Carlos Ruiz scored the 85th goal of his MLS career when he netted a spectacular winner as the Philadelphia Union beat the Chicago Fire 2-1 at PPL Park to go top of the Eastern Conference.
The Union took the lead when Michael Farfan scored the first goal of his MLS career but the lead lasted just four minutes when Dominic Oduro levelled before Ruiz scored what turned out to be the winner with 14 minutes left.
The Guatemalan striker fired in a fierce 30-yard shot which sailed over Fire keeper Jon Conway, hit the bar and bounced down over the line.
Mehdi Ballouchy scored an injury-time equaliser as the New York Red Bulls claimed a 2-2 draw against the Houston Dynamos at the Robertson Stadium.
New York had taken a first-minute lead when Dane Richards smashed home but Brad Davis converted a penalty to level in the 12th minute. An 82nd-minute goal by Koke looked to have won it for the hosts before Ballouchy headed home.
The San Jose Earthquakes beat the New England Revolution 2-1, Ellis McLoughlin putting the hosts ahead in the 77th minute and Bobby Convey doubling the lead. Chris Tierney pulled one back with four minutes remaining, to no avail.