Kazmir (10-3) won for the fifth time in his last six decisions. He walked two and struck out eight, improving to 6-1 in eight home starts.
Edwin Encarnacion drove in a run in the first inning for the Blue Jays and then had to leave the game with right quad soreness.
Mark Buehrle (10-6) pitched well but remained winless in six starts since June 1. He gave up three runs and 10 hits over six innings. Buehrle walked one and struck out three. He had a four-game winning streak against the A's end.
On a day when the A's traded for two top pitchers, they turned to their steady veteran to extend their hold as the AL's best pitching staff.
Kazmir retired 20 of 23 hitters after giving up singles to Jose Reyes and Melky Cabrera to start the game.
Encarnacion was hurt beating out a possible double play ball, allowing Reyes to score and putting the Blue Jays ahead. Encarnacion stepped on the first base bag, limped for a few steps and then tumbled to the ground.
Donaldson hit his 19th home run of the season, a solo shot over the fence in center field with two outs in the third to tie the game.
Crisp and Gentry hit bloop singles into right field that scored runs in the fourth. Lowrie added an RBI double in the eighth. He later scored on a passed ball.
Cabrera, who had two hits, was thrown out at the plate to end the eighth. A review upheld the decision.
The Blue Jays are 2-7 over their past nine games and have dropped five straight on the road.
NOTES: The A's optioned LHP Tommy Milone to Triple-A Sacramento to pave the way for RHP Jeff Samardzija to make his A's debut on Sunday. . The Blue Jays claimed OF Cole Gillespie off waivers from Seattle. He's expected to start Sunday. . Toronto OF Jose Bautista is expected to play in right field on Sunday after getting a couple days as DH to help him rest a sore hamstring. . Blue Jays IF Steve Tolleson was held out of the starting lineup with a twisted ankle. . RHP Drew Hutchinson (6-6, 3.81) will start Sunday's series finale for the Blue Jays. Hutchinson struck out a season-high 10 in his last start, a 4-1 victory over Milwaukee. . Samardzija is 0-2 with a 3.91 ERA over his last four starts. . A's 1B Brandon Moss was not in the lineup after spraining his ankle on Friday. ''It's sore, but it's nothing serious,'' Moss said.