Harrell (10-10) had three consecutive quality starts in which he received no-decisions before coming within one out of getting a quality start in his previous outing. That was the case again on Wednesday, when he allowed five hits and three runs and struck out seven in 5 2/3 innings.
"They have some guys that can hit the ball, and you're trying to work your way through the game and get them out," Harrell said. "A couple of times, I just tried to challenge them, and good hitters, when you make a mistake over the plate, they hit the ball. I thought overall the start was really good. They didn't hit many balls hard except those two balls."
It was the 20th homers of the season for both Freese and Molina, giving St. Louis a club-record five players with at least 20 in a season. Molina became the first Cardinals catcher to hit 20 homers since Ted Simmons socked 21 in 1980.
"I can't lie, I feel so good," Molina said. "I've never hit 20 before. It does feel good. To get the win feels better. It was a good night for the Cards."
Astros shortstop Jed Lowrie doesn't consider St. Louis to be a team of mashers.
"I think those guys do a really good job of taking what they're given," he said. "I don't think that they go up there trying to think about hitting home runs. If they get a pitch they can hit out, they're going to hit it out. For the most part, they keep it pretty simple and do what it takes to win."
The Astros, who have zero players with more than 16 home runs, could use some long-ball threats. They were 1-for-10 with runners scoring position -- falling to 2-for-21 in the series -- as Lance Lynn shut them down for 6 1/3 scoreless innings. The righty picked up his 16th win -- allowing three hits and striking out five.
Jose Altuve led off the game with a double for the Astros, before Lynn (16-7) sent down the next nine batters he faced. He was pulled after giving up a one-out double to Brandon Laird in the seventh inning after throwing 102 pitches.
"He worked quick, he got ahead with his fastball and changed speeds enough to keep guys off-balance," Lowrie said. "He's got a really good fastball. It's real easy and has pretty good command, so when he can get ahead with that he can be tough."
Harrell (10-10) struck out the side in the first on 17 pitches, and Allen Craig singled on the first pitch he threw in the second. Freese hit a two-run homer one out later to give the Cardinals a 2-0 lead. Molina homered with one out in the fourth to make it 3-0, and the Cards added a pair in the eighth off Mickey Storey.
"You can't make a mistake to a team like this," Astros interim manager Tony DeFrancesco said. "The middle of the lineup, you've got guys with 29 homers, there's 20, there's 19. It's a powerful offense that if you make a mistake they're going to hurt you. They're guys not only looking to pull, but to spray the ball all over the field."
Harrell didn't appear to be happy when he was removed from the game with two outs and runners at first and second base.
"I felt like my stuff was getting better later in the game, and I felt like I was at the point with two on, I could get a ground ball," he said "He makes the decisions. We go with it. I was frustrated more with myself than anything else."
Houston got singles from Brett Wallace and Laird, and Lowrie reached on an error to load the bases with one out in the ninth. The Cardinals summoned closer Jason Motte from the bullpen, and he struck out Chris Snyder and Jimmy Paredes swinging to end the game for his 37th save.
"We keep competing, we keep grinding it out," DeFrancesco said.