The Astros, who won for the first time in five games at Wrigley Field this season, improved to 12-47 on the road, the worst mark in the majors.

Harrell (10-8) struck out seven and allowed one run on six hits. He has won three of his last four starts.

Houston started the scoring early as Moore sliced a double into the gap in left-center to score Jose Altuve in the first. Moore, who came up with the Cubs in 2006, added a solo shot

Wallace crushed a 1-2 curveball from Chris Volstad to straight away center for his fifth homer - a three-run blast in the third - and Martinez sparked a five-run sixth with a three-run shot. It was Martinez's first homer with Houston and his first since May 13, 2011.

Volstad (0-9) allowed four runs on eight hits over five innings. He has lost 14 straight decisions dating to July 10, 2011.

Moore and Altuve each had three hits and scored two runs for Houston.

GAME NOTEBOOK: The home team had won all seven previous meetings between the teams this season. … Every Astros starter except rookie Brandon Barnes had a hit. ... Houston's 10 runs are its most since an 11-9 win June 10 at the Chicago White Sox. … Martinez's three RBIs matched a career high. … Houston has had only two games this season with two homers of three runs or more - both against the Cubs.