Jose Reyes' solo homer in the seventh inning was the difference, as Toronto topped Oakland, 5-4, in the second edition of a four-game set.
Reyes finished with two RBI, while Jose Bautista also went deep and drove in a pair of runs for the Blue Jays, winners in four of their last six efforts.
Mark Buehrle (8-7) worked 5 1/3 innings for the win, allowing seven hits and three runs with five strikeouts and two walks. Casey Janssen made things interesting in the ninth, but held on for his 21st save.
Josh Reddick clubbed two homers and knocked in three runs for the Athletics, who suffered their fourth defeat in five.
"It's kind of unbelievable," said Reddick, who struck for three homers and five RBI in a 14-6 win on Friday, "But I definitely went up there today thinking I had a shot to hit at least one. After last night, I had nothing but confidence up there."
Recalled from Triple-A Sacramento prior to the game for his first MLB start, Sonny Gray (0-1) lasted six full frames and gave up four runs -- two earned -- on four hits.
"Early on, I was missing with my fastball, falling off a little," Gray said. "I don't know if that's because I was anxious or what, but the longer the game went, the more comfortable I started becoming and I was just able to make my pitches a lot more efficiently than early in the game."
Reddick kept his club in the contest, denting Janssen for his fifth longball in the last two games to begin the ninth and pull the A's within 5-4. He became only the second player in Athletics history to pull off the feat, joining Mark McGwire, who did it in both 1987 and 1995.
Alberto Callaspo singled and Coco Crisp reached with a bunt base hit, but pinch-hitter Stephen Vogt's sacrifice bunt attempt turned into an out at third. Jed Lowrie flied to center and Yoenis Cespedes fanned swinging to end the rally and the game.
Bautista put the Jays on the board with a two-run shot in the first, one batter after Maicer Izturis worked a walk.
Oakland evened the score in the second as Chris Young walked, stole second and scored on Reddick's two-run shot, but Toronto moved in front again in the home half on a Reyes RBI groundout.
Colby Rasmus singled in Bautista to make it 4-2 for the hosts in the third, and though Nate Freiman's fly to left plated Cespedes in the sixth, Reyes restored the Jays' two-run edge in the home seventh when he reached down and clubbed a solo shot into the second deck in right.
Toronto leads the season series, 3-2 ... Buehrle has won his last three decisions ... Gray had tossed four innings of scoreless relief during two July appearances for Oakland ... A's catcher Derek Norris posted a career-best three hits, but left the game in the ninth with what was later called back spasms ... Prior to the contest, the Jays activated pitcher Drew Hutchison from the 60-day disabled list and optioned him to Triple-A Buffalo, placed pitcher Juan Perez on the 60-day disabled list and recalled pitcher Mickey Storey from Buffalo ... To make room for Gray, the A's designated infielder Adam Rosales for assignment.