Wei-Yin Chen pitched into the seventh inning and the Orioles took advantage of a great defensive play and a base-running gaffe by the Rangers to edge Texas, 3-1, in the opener of a three-game series.
Matt Wieters socked a solo homer and Nate McLouth went 2-for-4 with an RBI for the Orioles, who started the post All-Star break by winning for the fifth time in six games.
Chen (5-3) surrendered eight hits and a run over 6 1/3 frames to win his third straight start. The lefty, who celebrates his 28th birthday Sunday, has won all three of his career starts against the Rangers.
Jim Johnson worked out of trouble in the ninth inning to notch his major league-leading 34th save.
Nick Markakis took a home run away from Adrian Beltre in the fourth inning and the Orioles took advantage of a base-running mistake by Jeff Baker in the sixth.
"Obviously you'd like to be able to score some more runs, but when you win with pitching and defense, that's going to set you up for the long haul," Wieters said.
Derek Holland (8-5) allowed six hits and three runs and struck out six over eight innings, but lost for the first time in his last six starts.
Craig Gentry drove in the only run for Texas, which went 0-for-10 with men in scoring position and left 10 on base. The Rangers lost for the fifth time in six games.
"Opportunities were there, we just didn't cash them in and they did," Rangers manager Ron Washington said. "That's what the game is about...opportunities and taking advantage of them. We just didn't tonight."
Texas stranded a runner at third in the seventh when Darren O'Day came in to retire the final two batters after Ian Kinsler doubled in Chen's final batter he faced.
Pinch-hitter David Murphy singled and Kinsler was hit by a pitch in the ninth, but Elvis Andrus grounded into a force play to end the game.
Wieters homered to left field with two outs in the second, and Brian Roberts scored on McLouth's double to right field in the third for a 2-0 margin.
The Orioles were caught off guard in the fourth when the Rangers cut the deficit in half. First, though, Markakis made a leaping catch at the wall in right to rob Beltre of a homer.
Baker then singled. As soon as Mitch Moreland took ball four for a walk, Baker walked to second, but raced to third as Chen had his back to the play and third baseman Manny Machado was playing back to prepare for Gentry's at- bat. The stolen base resulted in a run when Gentry flied out to right field.
Baltimore got that run back in the next inning when Markakis doubled to left- center. The hit, which landed just in front of a diving Jurickson Profar, scored Machado.
The Rangers ran themselves into a crucial out in the sixth. Baker singled, and with one out Gentry doubled to right-center. Third base coach Gary Pettis made the signal to send Baker home, but then put up the stop sign when the ball came into the infield quickly. Baker was thrown out trying to scramble back to third.