Wilson Betemit's two-run single in the eighth inning was the difference as the Baltimore Orioles edged the Toronto Blue Jays, 7-5, to open a three-game series at Rogers Centre.
Adam Jones added a home run and two RBI, while Nolan Reimold and Robert Andino also homered for the Orioles, who snapped a three-game slide.
Starter Tommy Hunter allowed five runs -- four earned -- on six hits and two walks through six-plus innings before Darren O'Day (1-0) tossed a scoreless inning of relief to earn the win.
Darren Oliver (0-1) gave up the deciding run in the eighth inning to suffer the loss. Brandon Morrow gave up four runs on six hits and a walk through a seven-inning start for Toronto, which had won its previous two.
Yunel Escobar, Kelly Johnson, Edwin Encarnacion and Colby Rasmus each went deep in defeat.
Jason Frasor took the mound for Toronto in the eighth inning with the Blue Jays holding a 5-4 lead and gave up a leadoff single to Reimold before fanning J.J. Hardy and getting replaced by Oliver.
Nick Markakis greeted Oliver with a base hit and after Jones struck out, Matt Wieters worked a walk to load the bases. Betemit stepped up next and slapped a ball up the middle, scoring Reimold and Markakis to put the Orioles on top for good.
Casey Janssen fanned Mark Reynolds to end the inning and keep it a one-run game.
Pedro Strop then faced the minimum in the bottom of the eighth before Reimold hammered a ball into the left-field bleachers in the top of the ninth to give Baltimore a cushion.
Jim Johnson put the tying runs on base with two outs in the bottom of the ninth when he allowed a single to Brett Lawrie and hit J.P. Arencibia with a pitch, but he induced a soft fly ball to right by Escobar to earn his third save of the year.
Reimold led off the game with a double, moved to third on a Hardy groundout and came home on Markakis' sacrifice fly to left to give Baltimore the early advantage.
But Johnson hammered a shot over the left-field wall in the bottom of the frame to knot the game at 1-1.
The Orioles were able to regain the lead in the fourth when Markakis led off the inning with a double into left and then crossed the plate on Jones' base hit up the middle.
Toronto, however, answered again with a run in the bottom of the fourth when Reimold lost an Adam Lind fly ball to left-center field in the lights and Jose Bautista scored from first base on the error.
Lind later moved to third when Eric Thames reached first on a missed catch error by first baseman Chris Davis, but Lawrie grounded out to third to end the inning and keep the game tied at two.
After Andino smacked a solo home run over the center-field wall in the top of the fifth, Rasmus and Escobar both went deep in the bottom of the inning to give Toronto its first lead of the game, 4-3.
Jones then blasted a homer to straightaway center field in the sixth to knot the game again before Encarnacion's shot into the left-center field seats in the home half put the Blue Jays on top, 5-4.
Prior to the game, Toronto placed pitcher Sergio Santos on the paternity list and recalled pitcher Evan Crawford from Double-A New Hampshire...Baltimore went 3-for-6 with runners in scoring position and left four men on base, while Toronto hit 0-for-6 with runners in scoring position and stranded five.