Mark Buehrle did his part and went 8 innings for the Jays, only to see his 2-1 lead evaporate into a 4-2 loss to the White Sox.
A costly error by shortstop Jose Reyes led to three unearned runs for the ChiSox in the bottom of the 8th.
Sox lefty Chris Sale completed the game for his 7th win of the season, while Buehrle failed to pick up his 10th.
Reyes mistake started the eighth, as third baseman Gordon Beckham reached first on Reyes’ failure to field a routine ground ball to short.
Adam Eaton then singled to center. Jose Abreu hit a game-tying single to center, before Melky Cabrera followed with a two-run double.