"The offense was huge today," Harrell said. "We got an early lead, and then I kind of settled in and was just trying to pitch to keep us in the game, keep us in the lead. That made it easier for me, and the defense played great behind us, too."
Manager Brad Mills admitted that Harrell is making a strong case to be named the club's Most Valuable Player this season, which is even more unlikely when you consider that at one point this spring, Harrell was out of the running for a spot in the rotation.
"He is making a case, a very strong case," Mills said. "He throws strikes, he works fast and keeps everybody on their toes. When you get in a situation like that, guys know that they're not going to be on defense for a long time because he's going to get them back in the dugout and ready to hit."
And hit they did.
Wallace connected on a three-run homer in the third inning off winless Cubs starter Chris Volstad (0-9), and Martinez's three-run shot was the big blow in a five-run fifth inning that gave the Astros a nine-run lead. Scott Moore (3-for-5) hit two doubles and added a homer.
The 10 runs were the most the Astros scored in a game since they beat the White Sox, 11-9, on the south side of Chicago on June 10.
"I think tonight we did a really good job of not being satisfied putting a ball in play," Moore said. "We got pitches to drive, and we drove them. I think that was key tonight. We had a lot of extra-base hits and a couple of three-run homers, and that was the difference. Instead of putting the ball in play, we got pitches to drive."
Harrell even got in on the offensive fun, going 1-for-3 with a walk and a run scored. Every player in the starting lineup except Brandon Barnes had at least one hit as the Astros bashed out 14, seven for extra bases.
Harrell, who has allowed two runs or fewer in each of his last seven outings and nine of 10 since June 22, threw 78 of his 104 pitches for strikes.
"Harrell came right after us," Cubs manager Dale Sveum said. "It looked like he threw 90 percent fastballs, and we didn't capitalize on his aggressiveness at all. We took a lot of fastballs and we weren't real aggressive on the fastball for a guy who throws a lot of fastballs."
Wallace, who hit five homers in 336 at-bats with the Astros last season, connected on his fifth homer of 2012 in the third inning with a mammoth three-run blast to straightaway center that landed on the roof of the batter's eye and put Houston ahead, 4-0. He has matched last year's home run total in only 83 at-bats.
"I hit that one pretty square, and it felt good to get a big hit right there and put us on the board and put us ahead by a few more runs," Wallace said. "It's just about picking each other up at-bat to at-bat, and that was the cool part. The guys got on in front of me, and it's good to drive those guys in when you have those opportunities."
Houston sent nine batters to the plate in the sixth and scored five more runs off reliever Lendy Castillo. Cubs shortstop Starlin Castro made a costly error that led to two unearned runs, but the big blow was Martinez's three-run blast, which landed nearly in the same spot as Wallace's homer.
The homer was the first for Martinez with the Astros and his first in the Major Leagues since he took Bud Norris deep on May 13, 2011, while he was playing for the Mets.
"Yeah, it felt very good," Martinez said. "The last couple of games, I've tried to hit the ball to the outfield, but today I felt very good at home plate and saw the ball better, and I think my swing was better."
Harrell began his career with the White Sox, who drafted him in the fourth round in 2004, but the Astros plucked him away on waivers last July. Tuesday marked his first career start at Wrigley Field, and he certainly looked at home.
"I know a lot of people from here," Harrell said. "I made a lot of good friends when I was with the White Sox, and so I had quite a few people here. One of my buddies from back home is living up here now, and it was one of those nights it felt good going out there and pitching in a historic park like Wrigley."