Alba Torrens scored 25 points as Spain broke open a 59-58 game after three quarters to beat Serbia 85-70 on Thursday and remain unbeaten in Olympic women's basketball pool play.
Torrens and Chicago Sky post player Astou Ndour, who finished with 20 points, took over the scoring load as Spain outscored Serbia 26-12 in the fourth quarter.
Both of Spain's top scorers in the game played on the 2016 team that took silver in Rio.
Canada 74, South Korea 53
After sticking within four points of Spain in its opening game, South Korea faded on Thursday, trailing by five at the half but then managing only 11 points in the third quarter as Canada took a 74-53 win.
Bridget Carleton had 18 points, and Minnesota Lynx teammate Natalie Achonwa had 14 points and 10 rebounds for Canada, which lost its opener 72-68 to Serbia.
Canada and Serbia are tied for second in the group at 1-1, but Canada has the more difficult matchup in its final group-stage game against Spain.