The first quarter was initially close, Munn's free throw giving GB a 5-4 lead, but Canada dominated after that and the quarter ended 20-11.
Britain flew out of the blocks in the second period and after a fine three-pointer by Pollock the scores were 24-23 to Canada. However, Canada eased some of the pressure and the sides were poised at 34-29 at the half.
Inside four minutes of the third quarter Canada had scored seven without reply and by the end of the period were 52-36 up, leaving GB with a huge task in the final period.
The first four minutes of the final quarter were tense and low-scoring as Canada looked to hold their lead, but they were still outscoring Britain by nearly two points to one.
GB could not overturn the deficit and Canada took the win 70-54.