With the game tied 2-2, Toronto loaded the bases with none out and was primed for the go-ahead run. Baltimore's Darren O'Day, however, struck out Russell Martin, Dioner Navarro and Kevin Pillar to end the threat.
In the ninth Caleb Joseph gave Baltimore the lead with an RBI single off reliever Aaron Loup. Manny Machado then drove home two more runs with a double off of Ryan Tepera as the Orioles went on to defeat the Blue Jays 5-3.
"We had them on the ropes, but there's nobody tougher out there than O'Day," said Blue Jays manager John Gibbons. "You look at his numbers, look at what he's done over the years, he's a tough at bat. We were close to maybe a three-run homer (on a foul ball by Navarro), but he gets three punch-outs."
O'Day (3-0) pitched a scoreless inning for the win while Loup (2-4) picked up the loss after allowing three earned runs on two hits in two-thirds of an inning.
"If you can stay calm in those situations, you have an advantage," said O'Day. "It's not ideal. I don't like doing that, necessarily. You've just got to focus on each pitch and when you do that, you can stay in the moment.
"It's tough here when they start hitting balls all over the place to keep your cool. All our guys did a great job today."
Toronto (37-33) threatened again in the ninth, but only managed one run off of closer Zach Britton courtesy an RBI single from Jose Bautista.
With the win the Orioles (35-33) avoided a third straight loss while Toronto's three-game winning streak came to an end. The Blue Jays had won nine straight at home entering Saturday's game.
Kevin Gausman (1-0), who was activated off of the 15-day disabled list (right shoulder tendinitis) prior to the game, made his first start of the season. The Orioles right-hander went five innings, allowing two earned runs on four hits.
Mark Buehrle (7-4) entered the start having allowed just three earned runs in his last 30 innings, over four starts dating back to May 29. The left-hander allowed two earned runs on six hits while striking out five in seven innings of work.
"Today was a good example of getting away with a lot of stuff," said Buehrle of his 500th career appearance. "I wasn't as sharp as I've been my last four or five outings. This one I missed location. They either fouled it off or didn't put the ball in play. Today was a lot of luck."
The Orioles got to Buehrle early.
Machado doubled and scored in the first inning.
Toronto responded in the bottom half of the first as Jose Reyes led off with a double of his own. The Blue Jays shortstop scored two batters later on a shallow sac fly to centre from Edwin Encarnacion.
The Blue Jays then took the lead in the second
Martin took a Gausman pitch off his back elbow to lead off the inning. The catcher advanced to third on a Navarro single and scored on a Gausman wild pitch to Pillar.
Baltimore tied it 2-2 in the sixth when Machado scored on a Delmon Young sacrifice fly.
Notes: The announced attendance at the Rogers Centre was 46,018 marking the second sellout of the season. … The Blue Jays will hand the ball to RHP Scott Copeland (1-1) for Sunday's series finale while the Orioles counter with RHP Chris Tillman (5-7).