Alberto Callaspo hit the go-ahead two-run double in a three-run eighth inning, as Oakland rallied past Toronto, 6-4, in the third edition of a four-game series.
Brandon Moss slugged a two-run homer, while Josh Donaldson and Chris Young added an RBI apiece for the Athletics, who have won two of three in the set.
Ryan Cook (4-2) tossed 1 1/3 innings of scoreless relief for the win, while Grant Balfour walked a tightrope in his one frame, but earned his 30th save.
Oakland manager Bob Melvin was rewarded with his 700th career victory.
"Never a dull moment," Melvin deadpanned. "Excruciating. We found a way to win but it wasn't pretty."
Jose Reyes and Maicer Izturis drove in a run each for the Blue Jays, who left the bases loaded in the bottom of the ninth and dropped their third game in four.
Darren Oliver (3-3) was charged in defeat with three runs on four hits while recording just two outs.
Oliver took over for starter R.A. Dickey in the eighth in a 3-3 tie and it didn't take long for the visitors to strike.
He allowed a one-out single to Josh Reddick and walked Donaldson before fanning Moss. Callaspo then doubled off the wall in left and off the tip of the glove of Emilio Bonifacio to score two, and after a Stephen Vogt base hit, Young smacked a pinch single which brought in Callaspo for a 6-3 A's edge.
"They just ended up getting a lucky one there with two outs," Jays infielder Brett Lawrie said in reference to Callaspo's hit. "That kind of stung us a little bit."
Balfour had his own troubles locking things down. He walked Edwin Encarnacion, who moved to second on an Adam Lind groundout. After Colby Rasmus struck out, Lawrie's double pulled the Jays within two. Lawrie advanced on a wild pitch and J.P. Arencibia eventually walked, then Rajai Davis worked a base on balls to fill the sacks, but Reyes grounded out to end the contest.
"That was horrible today, no doubt about it," said Balfour. "I was frustrated, I was fighting it, I'm not going to lie. I was fighting myself, gave up one run and salvaged the game. You've almost got to be happy to give up one run and save the game right there because I didn't throw well at all."
Toronto picked up a run in the second thanks to shoddy Oakland defense. Lind reached on a Moss fielding error, Rasmus walked, and Lind scored when A's shortstop Eric Sogard airmailed his throw to first on a Lawrie grounder.
Oakland moved ahead in the sixth. Yoenis Cespedes hit a leadoff double and moved up on a wild pitch before crossing home on a Donaldson single. Moss followed with a two-run blast to dead center to make it a 3-1 game.
The hosts responded to tie in the home half on an RBI single from Reyes and a sacrifice fly from Izturis.
Oakland hurler A.J. Griffin worked 5 2/3 innings, giving up five hits and three runs -- two earned -- while walking six batters ... Dickey finished with six hits and three runs on his ledger over a seven-inning outing ... The Blue Jays wore special red jerseys for Toronto's celebration of Canada Baseball Day ... Lawrie finished with a game-high three hits in defeat ... A's pitchers issued 11 walks.