Josef Martinez scored a pair of second-half goals, giving him an MLS-leading five on the season, and United turned in another dominating performance with a 4-0 victory over the Chicago Fire on Saturday.
Reigning MLS champions Seattle Sounders recorded their first win of the season with a comfortable 3-1 victory over New York Red Bulls on Sunday.
Diego Valeri scored twice and David Guzman got the game-winner as the Portland Timbers beat the Houston Dynamo 4-2 Saturday night.
The New England Revolution spent more than an hour ahead in their match on Saturday against FC Dallas at Toyota Stadium, but the hosts came roaring back in the second half to notch a 2-1 victory.
RESULTS
New York City 1-1 Montreal
Vancouver 0-2 Toronto
Atlanta United 4-0 Chicago
DC United 0-2 Columbus
Orlando 2-1 Philadelphia
FC Dallas 2-1 New England
Sporting KC 2-1 San Jose
Colorado 2-2 Minnesota United
Real Salt Lake 1-2 LA Galaxy
Portland 4-2 Houston
Seattle 3-1 New York Red Bulls