Defoe scored both goals Saturday in a 2-1 road victory against Seattle Sounders FC, helping Toronto start their season with a win for the first time in club history.
Defoe opened the scoring in the 17th minute when he collected a through ball from midfielder Jonathan Osorio and slid the ball past former Toronto goaltender Stefan Frei.
It was Defoe's first attempt on goal in his MLS career.
The England international struck again seven minutes later when he intercepted a Seattle back pass and blasted a shot past Frei.
Defoe was one of three big-ticket designated players signed by Toronto during the off-season, along with American midfielder Michael Bradley and Brazilian striker Gilberto.
Toronto hosts D.C. United in its home opener this Saturday.