Toronto's title defence failed to ignite after the winless MLS champion crashed to consecutive defeats, while Atlanta United routed a 10-man Vancouver Whitecaps side.
Saturday saw Sebastian Giovinco's Toronto upstaged by Canadian rivals Montreal Impact 1-0 at Stade Olympique.
Toronto has been flying high in the CONCACAF Champions League , where the club is set to meet Mexican giant America in the semifinals, but the MLS titleholder has struggled domestically.
Greg Vanney's side is still searching for its first win of the MLS season after Jeisson Vargas' deflected shot four minutes before halftime lifted the Impact to victory number one in 2018.