Toronto FC maintained their MLS Supporters' Shield pace, while FC Dallas coughed up a 3-1 lead at home to Houston Dynamo.

Former Juventus forward Sebastian Giovinco was at the forefront again as Eastern Conference leaders Toronto accounted for Philadelphia Union 3-0 on Wednesday.

Giovinco opened the scoring at BMO Field, while Nicolas Hasler and Jozy Altidore were also on target for Toronto, who extended their lead in the race for the Supporters' Shield to seven points over New York City.

The deadlock was broken by Giovinco's moment of brilliance after 10 minutes in Toronto.

A free-kick specialist, Italian star Giovinco curled a set-piece into the top corner, while Hasler's header on the half-hour mark doubled the lead.

United States international Altidore sealed the victory in the 57th minute as Toronto extended their unbeaten streak to eight matches.

Dallas missed the chance to close the gap on Western Conference leaders Seattle Sounders after crumbling in a 3-3 draw with the Dynamo.

Reigning MLS Cup champions the Sounders were held to a 1-1 draw by Vancouver Whitecaps.

However, Dallas conceded twice during the final 19 minutes to share the spoils after three goals in six minutes via Tesho Akindele, Maynor Figueroa and Maximiliano Urruti had given the hosts a comfortable lead.

Real Salt Lake crushed 10-man San Jose Earthquakes 4-0, an own goal lifted DC United to a 1-0 win against Atlanta United, former Chelsea and Arsenal defender Ashley Cole was sent off as LA Galaxy's winless league run extended to nine games following a 2-0 loss at Columbus Crew, while Portland Timbers edged Colorado Rapids 2-1.