Texas owned a 1-0 lead going into the ninth, but Miguel Tejeda singled in the tying run to force extra innings and the Orioles then broke things open against relievers John Rheinecker (3-3) and Wes Littleton.
A single, walk and fielding error accounted for one run in the 10th, after which Melvin Mora produced an RBI single and Roberts hit one out to right-center.
That made a winner out of Jamie Walker (2-2), who pitched 1 2/3 innings of relief.
The Rangers scored twice in the bottom of the 10th against Fernando Cabrera, but they still lost for the ninth time in 10 games.
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