Greek Giannis Antetokounmpo brought all his NBA experience as the Milwaukee Bucks small forward made 27 points, hitting 11 rebounds and three assists.
However, he wasn't prepared for Spain guard Sergio Llull, who combined with first-time Olympian and Memphis Grizzlies forward Santi Aldama to make 32 points in the match.
"We had a lot of faith even with this up and downs in score. Of course, we had some slumps, little slumps. But overall we controlled rebounds which was a little flaw in the last few games," said Spain coach Sergio Scariolo.
Canada were up to the task of upsetting third-ranked Australia, who chased the North Americans throughout the game, but were unable to keep up.
Chicago Bulls point guard Josh Giddey led the Australians with 19 points, seven rebounds and six assists.
But Canada's superior shooting, with the combined efforts of RJ Barrett and Shai Gilgeous-Alexander, saw them making up to 40 points.
Hosts France face Japan and Germany take on Brazil in Group B later on Tuesday.