Reigning MLS champion Toronto FC suffered its second straight defeat to open the season in falling 1-0 away to the Montreal Impact on Saturday.
Jeisson Vargas scored the only goal for the Impact, who were the only team to win at Toronto's BMO Field last season.
Toronto made a splash earlier this week by advancing to the CONCACAF Champions League semifinals past Liga MX title-holders Tigres, but the Reds' MLS form has suffered with their attention split.
TFC coach Greg Vanney made three changes to his side from the XI that played in Mexico on Tuesday but still started his big trio of Sebastian Giovinco, Jozy Altidore and Michael Bradley.
Vargas' shot took a deflection before beating Toronto goalkeeper Alex Bono in the 41st minute to put Montreal ahead, and Altidore had an attempt cleared off the line in the second half as the Impact held on for their first win of the year after two defeats.