The Seattle Sounders moved three points ahead of the LA Galaxy - who host the New York Red Bulls on Sunday - with a 4-2 home win over strugglers Chivas USA.
Seattle were heavy favourites against a Chivas side who had not won in 11 matches - losing 10 of them.
But Erick Torres gave them a scare with a 12th-minute opener for Chivas, tapping into an empty net after Felix Borja's shot was parried.
And although Obafemi Martins quickly responded with a 25-yard stunner, parity did not last long, as Jalil Anibaba turned a Torres cross into his own net.
Chivas began to dream of a first win since July but those thoughts were quashed by half-time as Lamar Neagle and Clint Dempsey both netted composed finishes for Seattle.
And Martins got a second six minutes after play resumed with a chipped finish as the Sounders ended a two-game losing streak of their own.
Toronto's revival under new coach Greg Vanney gathered pace with an excellent 3-2 home win over the Portland Timbers.
Vanney, who took on the Toronto top job last month, saw his side trail 2-0 inside 20 minutes after a Steven Caldwell own goal followed Fanendo Ali's opener.
Nick Hagglund scored twice in three second-half minutes, though, setting up a thrilling conclusion.
And Michael Bradley netted the winner when his 35-yard free-kick from the left inadvertently bounced in.
Toronto have climbed up to sixth in the Eastern Conference.
Vancouver also came from behind to win - two Pedro Morales goals in the last 30 minutes giving the Whitecaps a 2-1 victory over Real Salt Lake.
Eastern Conference leaders DC United beat Philadelphia Union 1-0 thanks to Luis Silva's 10th-minute strike.
Elsewhere, Columbus Crew beat Montreal Impact 2-0 and Western Conference strugglers Colorado Rapids and the San Jose Earthquakes played out a 1-1 draw.
