The best team in the Western Conference, San Antonio (14-7) fell to a Chicago squad that had won just one of their last six games.
The Silver Stars did have an opportunity to extend the game in the waning seconds of overtime, but Becky Hammon's shot was off the mark.
Although she did not provide the game-winning bucket, Jia Perkins had a huge game for the Sky, coming off the bench to lead all scorers with 27 points including nine in the fourth quarter.
Canty scored 13 points for Chicago (10-13) and Armintie Price added another 12.
Sophia Young lead the Silver Stars with 25 points and Hammon finished with 20.
Asjha Jones scored on a short jump shot with three seconds to play to lift the Connecticut Sun to an 81-79 victory over the Houston Comets.
Katie Douglas scored 25 points and Jones added 22 as the Sun won their sixth consecutive game to give coach Mike Thibault his 100th career victory.
Tina Thompson and Tamecka Dixon scored 18 points each for Houston.
The Comets took their final lead, 79-77, on a bank shot by Thompson with 53 seconds to play.
The Sun (12-11) pulled even on a jumper by Evanthia Maltsi with 35 seconds to play, setting up the winning basket by Jones.
Maltsi scored 15 points and point guard Lindsay Whalen added 11 for Connecticut.
Also on Sunday, Sue Bird's three-pointer with 10 seconds remaining lifted the Seattle Storm to a 77-75 victory over the New York Liberty.
They were Bird's only points of the game and could not have come at a better time for the Storm, who squandered a nine-point lead with just over three minutes left.
Janel McCarville had made a layup to cap a 12-2 burst and give the Liberty a 75-74 lead with 30 seconds left.
And Tangela Smith scored a season-high 24 points to lead the Phoenix Mercury to a 106-93 victory over the Minnesota Lynx.
Smith made 4-of-5 from beyond the arc to help the Mercury roll to their second win in three outings.
Seimone Augustus had 23 points and Nicole Ohlde added 17 for Minnesota (5-19), who pulled within seven points with 4:12 left but got no closer.
Penny Taylor added 28 points - 19 in the second half - and nine rebounds for the Mercury.
Michael Bradley Photography
Vitality Nations Cup
Nottingham Forest's City Ground to host FA Women's Continental Tyres League Cup Final