Cowser, who replaced an injured Aaron Hicks in the third inning, lofted the ball just out of reach of a diving Kyle Schwarber down the left field line to score Gunnar Henderson.
Jordan Westburg and Ryan Mountcastle each hit solo home runs for the Orioles, who have won five of six
Orioles starter Dean Kremer gave up three hits and one run with three strikeouts and two walks in seven innings
Bryan Baker (4-3) earned the win after getting the final out of the eighth. Cionel Perez allowed a single and a walk but threw a scoreless ninth for his first save in two chances.
Schwarber had a sacrifice fly RBI and two walks for Philadelphia, while Nick Castellanos added an RBI single.
With runners on first and second and no outs in the eighth inning, Edmundo Sosa lined into a double play. Bryce Harper then singled to send Schwarber to second, and Castellanos singled him home to tie the game. Harper also tried to score but was thrown out at home.
Phillies starter Cristopher Sanchez tossed seven innings and allowed four hits and two runs with a career-high eight strikeouts and no walks. Craig Kimbrel (6-2) took the loss
Johan Rojas also had two hits and two stolen bases for the Phillies
The Orioles went ahead 1-0 in the second when Westburg hit a solo home run just inside the foul pole in right field. It was Westburg's first career homer
Rojas ripped a liner to center in the third and Hicks made a diving catch. Though the ball appeared to pop out of Hicks' glove, Rojas was ruled out. Hicks also left the game with a left hamstring cramp.
Trea Turner committed his second error, this time in the fifth against Jorge Mateo, and the Orioles placed runners at first and second with two outs. Austin Hays struck out to end the threat
In the bottom of the fifth, Rojas singled to right and the Phillies had runners at first and third with one out. Rojas then stole second and Schwarber hit a sacrifice fly to center, which scored Garrett Stubbs with the tying run. Turner struck out looking to end the inning and was soon ejected by home plate umpire Will Little for arguing
The Orioles regained a 2-1 advantage in the sixth on Mountcastle's 451-foot solo homer to center
--Field Level Media