OAKLAND, Calif. -- Former Chicago Cubs right-hander Jeff Samardzija will have a tough pitching act to follow Sunday afternoon when he makes his debut for the Oakland A's against Toronto.

Left-hander Scott Kazmir allowed just one run and three hits in seven innings Saturday night, leading the A's to a 5-1 victory over the Blue Jays as his new teammate watched from the dugout.

The A's beat the Jays for the third straight time and will go for a sweep in their four-game series Sunday with Samardzija on the mound.

Kazmir (10-3) struck out eight, walked two and was dominant after allowing a run in the first inning.

"That first inning I had a little bit of jitters," he said. "The first pitch of the second inning felt good, everything felt on time. Kind of went from there. Started building on every pitch. Everything felt great. I was able to throw my changeup, my slider and my cutter consistently. That's what kind of got me locked in."

Blue Jays left-hander Mark Buehrle (10-6) lost his fifth straight decision. He gave up three runs and 10 hits in six innings, including third baseman Josh Donaldson's solo home run in the third inning and second baseman Alberto Callaspo's double in the fourth when the A's scored twice.

A's reliever Luke Gregerson pitched a scoreless eighth, thanks in large part to two defensive gems.

First, Donaldson made a spectacular catch of second baseman Munenori Kawasaki's pop fly in foul territory on the third base side. Running full speed, Donaldson caught the ball and held on while slamming into the tarp.

"I felt like a running back trying to score a touchdown right there," Donaldson said. "I think I would have lost that battle, get stopped at the goal line."

With two outs, left fielder Melky Cabrera singled and designated hitter Jose Bautista laced a double to left. Cabrera tried to score, but the A's cut him down on a relay from left fielder Craig Gentry to shortstop Jed Lowrie to catcher Derek Norris. Toronto manager John Gibbons challenged the call, but it was upheld.

"He missed him by a good foot or two," an angry Bautista said. "I don't really know which replay they were looking (at), but clearly they must have had a different video feed than the one we had.

"It's pretty frustrating for you to battle as a team, keep the game close, for our pitchers to be doing what they're doing, for us to keep grinding three games and facing tough pitching, and somehow be able to get an opportunity to tie the game in the eighth inning and it all goes down the drain because somebody first initially made a bad call to begin with, and then it gets upheld by God knows who in some room in New York supposedly. This whole replay thing has become a joke in my eyes. I think they should just ban it."

Oakland extended its lead to 5-1 with two runs in the eighth. First baseman Nate Freiman singled and scored on Lowrie's double. Lowrie scored from third on a passed ball.

The Blue Jays' struggling offense received another blow in the first inning when first baseman Edwin Encarnacion, their leading home run and RBI man, injured his right quad while running to first after hitting a ground ball. A few steps after hitting the bag with his left foot, Encarnacion began hobbling and fell to the ground in pain. He was helped to the clubhouse by two trainers.

"I wouldn't guess it'd be a quick thing," Gibbons said. "He'll get an MRI tomorrow or the next day and we'll have a little better idea. He said he felt something pop in his quad. That's all I know right now."

Encarnacion drove in shortstop Jose Reyes from third base on his fielder's choice. Reyes opened the game with a single and moved to third on Cabrera's bloop single.

The A's pulled even in the third on Donaldson's solo shot, his 19th home run of the year and first since June 20 against Boston.

Oakland struck for two more runs in the fourth. Callaspo lined a two-out double to left and right fielder Stephen Vogt walked. Center fielder Coco Crisp blooped an RBI single to center, and Gentry brought Vogt home with a soft single to left.

After the first inning, Kazmir put on a show for Samardzija, who came to the A's along with right-hander Jason Hammel in a five-player trade.

"If you can get to him early, you probably need to because once he gets his rhythm going he gets awfully tough as the game goes along," A's manager Bob Melvin said. "He gets more and more unpredictable with his pitches."

NOTES: RHP Jeff Samardzija reported to the A's as his trade from the Chicago Cubs became official, and he'll start Sunday against Toronto. RHP Jason Hammel, who was also acquired from the Cubs, is expected to report to the A's on Sunday and start Wednesday at San Francisco. ... Oakland LHP Tommy Milone was optioned to Triple-A Sacramento, clearing a spot on the 25-man roster for Samardzija. Milone was 6-0 with a 2.62 ERA in his past 11 starts. "He was a little bit shocked," manager Bob Melvin said. "Understandably so. But you haven't seen the last of Tommy Milone here." ... Oakland 1B Brandon Moss (sprained left ankle) was out of the lineup, one day after being injured. "It's nothing serious," Moss said. "I think it will feel a lot better probably tomorrow or the next day." ... Toronto claimed OF Cole Gillespie off waivers from the Seattle Mariners. He's expected to report Sunday. ... Toronto 3B Steve Tolleson was out of the lineup with a sore ankle.