Walk-off loss: Donaldson's three-run homer in ninth lifts Oakland to win

What looked like an impressive win rapidly turned into a stunning loss in the bottom of the ninth inning. Down 4-2 when the inning began, Josh Donaldson hit a three-run, walk-off homer off Zach Britton as the A's stunned the Orioles 5-4 in the series and road trip opener. The Orioles had taken a 4-2 lead on Manny Machado's two-run homer in the top of the seventh. Britton came on to start the ninth and Yoenis Cespedes reached on an infield single to third. Brandon Moss followed with a bloop hit to right. Then Donaldson hit his 21st homer of the season on the first pitch from Britton to send the home crowd into a frenzy. Britton had recorded 10 straight scoreless appearances over a total of 10 innings until suffering his third blown save in 18 chances tonight. Earlier, Machado was loudly booed all night, but he quieted the Oakland crowd with a line drive, two-run homer down the left-field line. It broke a 2-2 tie and put the O's ahead 4-2 with nine outs to go. Machado's blast was his sixth homer in his last 13 games. Machado is 17-for-35 (.486) with three homers and five RBIs in nine games since returning from his suspension. He has reached base in a career-high 17 straight games, and is batting .415 (27-for-65) during that span. Donaldson's homer denied Chris Tillman the win. Tillman went 6 2/3 innings, allowed four hits, and two runs with one walk and six strikeouts on 103 pitches. Over his last eight starts Tillman has pitched to an ERA of 2.50 with seven quality starts. Over their last 34 games, O's starters have pitched to an ERA of 3.17. Down 1-0 in the top of the fifth, the Orioles took a 2-1 lead on Jonathan Schoop's two-run homer off Jeff Samardzija on a 3-2 slider. It was Schoop's seventh homer and he adds Samardzija to a homer hit list that includes Masahiro Tanaka twice, Francisco Rodriguez, Kyle Lohse and Drew Hutchison. Samardzija gave up six hits and four runs over seven innings in his third Oakland start. He had given up four runs over 15 innings in his first two American League starts. The Orioles fall to 52-43 with the loss. They lead the AL East by four games after Toronto's loss and New York's win tonight. In the second game of this series on Saturday night, Wei-Yin Chen (9-3, 4.15 ERA) will face former Oriole Jason Hammel (0-1, 3.60 ERA) who will make his second start for Oakland.