The Rangers outhit the Orioles 9-6, but could not come up with the big hit against Chen (5-3).
The only Texas run scored on a sacrifice fly in the fourth by Craig Gentry, who came off the disabled list prior to the game.
Jim Johnson, the major leagues' saves leader, appeared in the ninth to protect the Baltimore lead and soon ran into trouble. He gave up a leadoff single, hit a batter with two away and wound up facing the potential winning run in Elvis Andrus.
Andrus, however, grounded into a force play to end the game and Johnson collected his 34th save.