Tillman (5-2) limited the Astros to one run on three hits in the 113-pitch effort, working around a pair of walks.
Danny Valencia homered, Ryan Flaherty went 2-for-4 with an RBI and the Orioles scored twice on Houston errors en route to the triumph.
Lucas Harrell (4-7) was hung with the loss despite yielding just one earned run on five hits over seven full frames as the Astros saw their longest winning streak since 2005 broken.
Brandon Barnes went 2-for-4 with a solo homer in the loss.
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