Reigning MLS Cup champions Sporting broke a four-game losing streak with a 4-0 thrashing of struggling Chivas USA at the StubHub Center.

It saw Peter Vermes' side close to within two points of Eastern Conference leaders DC United, while it extended Chivas USA's winless run to 10 matches.

The visitors needed until the 39th minute to open the scoring through Dom Dwyer, who set the club's single-season scoring record with his 19th of the campaign.

Graham Zusi's wonderful lofted pass found Dwyer and the prolific goalscorer finished emphatically from inside the area.

Before half-time, it was 2-0.

Dwyer released Toni down the right and his shot struck the post before Benny Feilhaber stretched to put away the rebound.

Zusi added another in the 52nd minute as he cut in from the left before firing into the bottom corner.

Substitute Claudio Bieler added polish to the scoreline with three minutes remaining.

The Argentine cut out Jhon Hurtado's attempted back pass before rounding goalkeeper Dan Kennedy and finishing into an open goal.

The Sounders moved four points clear atop the Western Conference with an entertaining 3-2 win over Real Salt Lake.

Goals from Lamar Neagle, a stunning long-range effort, and Obafemi Martins had cancelled out Real Salt Lake midfielder Javier Morales' opener.

Joao Plata equalised for the visitors in Seattle in the 50th minute, only for them to be reduced to 10 men soon after when Nat Borchers denied Martins an obvious goalscoring opportunity.

The Sounders looked set to be denied until the 94th minute, when Australian substitute Andy Rose blasted a loose ball past Nick Rimando.