Patrick Vieira oversaw a thrilling 4-3 victory at the Chicago Fire in his first MLS match as New York City coach.

Vieira swapped parent club Manchester City for New York in the offseason, replacing Jason Kreis after the club missed the playoffs last season despite boasting David Villa, Andrea Pirlo and Frank Lampard. And the former France international's reign got off to the perfect start in their season opener on Sunday, thanks to a three-goal first half at Toyota Park in Chicago.

Playing in the absence of an underdone Lampard, New York City opened the scoring in the 10th minute when midfielder Thomas McNamara curled a shot in off the post. The Fire responded through Razvan Cocis nine minutes later, though New York City forward Tony Taylor restored the visitor's lead just shy of the half-hour mark before Khiry Shelton made it 3-1 in the 36th minute.

Kennedy Igboananike reduced the deficit four minutes into the second half, only for Mikkel Diskerud to re-establish New York City's two-goal buffer after 63 minutes. The Fire converted a 72nd-minute penalty via David Accam but NYCFC held on in the Eastern Conference.

A star-studded LA Galaxy side rallied to thrash DC United 4-1 as Ashley Cole and Nigel de Jong made their league bows.

The Galaxy trailed to a fifth-minute opener from Lamar Neagle before the home side piled on four unanswered goals in the second half.

MLS debutante Daniel Steres leveled proceedings in the 54th minute and substitute Mike Magee gave the Galaxy a 2-1 lead 10 minutes later.

The Galaxy ensured victory courtesy of goals from captain Robbie Keane and Magee in the final seven minutes of regulation.

Last season's Supporters' Shield winners New York Red Bulls were accounted for 2-0 by Toronto FC. Reigning MVP Sebastian Giovinco broke the deadlock from the spot with eight minutes remaining and Marco Delgado sealed the points in the 90th minute.

The defending champion, the Portland Timbers, continued where they left off following a 2-1 win at home to Columbus Crew.

In a rematch of the 2015 MLS Cup final, the Timbers reigned supreme after Diego Valeri and Fanendo Adi scored either side of Federico Higuain's 68th-minute overhead kick.

A pair of injury-time goals from Cyle Larin and Adrian Winter salvaged a dramatic 2-2 draw for Orlando City - missing Kaka - against visiting Real Salt Lake as both teams were reduced to 10 men in the first half.

In other results, Ignacio Piatti's brace inspired Montreal Impact to a 3-2 win at Vancouver Whitecaps in the absence of Didier Drogba.

The San Jose Earthquakes and Sporting Kansas City were 1-0 winners over the Colorado Rapids and Seattle Sounders respectively.

Daigo Kobayashi scored in the 90th minute as the New England Revolution claimed a 3-3 draw at the Houston Dynamo, while FC Dallas beat the Philadelphia Union 2-0.