Scott Moore went 3-for-5 with a solo homer and two RBI while Jose Altuve added three hits, including a run-scoring double, as the Astros evened their three-game series.
Lucas Harrell (10-8) limited the Cubs to one run on six hits over eight innings, walking two and striking out seven.
Chicago starter Chris Volstad (0-9) was touched for four runs on eight hits over five innings.
Darwin Barney provided the Cubs' only RBI.
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