Adam Wainwright, predictably, was his dominant self against the Houston Astros on Tuesday at Busch Stadium,

Already 12-1 with a 1.58 career earned run average against the Astros, who often were good when he faced them in the National League, the Cardinals’ righthander stopped Houston on five hits, fanning nine, over seven innings, in a 9-5 triumph on a steamy night.

The Cardinals moved 1½ games ahead of the suddenly dormant Pittsburgh Pirates in the National League Central Division race with their fourth straight win, rising to 20 games over .500 at 54-34, before a sellout paid house of 43,836.

There was some good news for the Astros, though. They won’t have to face Wainwright for at least three more years because of the interleague rotation.

Tying Washington’s Jordan Zimmermann for the league lead in wins at 12, Wainwright beat Houston for the seventh straight time and lowered his ERA against them by 0.01 to 1.57. He had 11 ground-ball outs, leaving pitcher Bud Norris’ liner to right in the fifth as Wainwright’s lone outfield putout.

“And that was not a good pitch or it probably would have been on the ground,” Wainwright said. “My philosophy, coming from the Dave Duncan era, is always to see how many grounders you can get.”

Manager Mike Matheny cited Wainwright’s curveball as his major weapon Tuesday night and, indeed, Wainwright got eight of his strikeouts with his variety of breaking balls, some hard, some not.

And there was no dispute when Matheny pulled Wainwright after the seventh.

“He’s always going to lobby (to stay in) somewhat,” said Matheny. “But I think he saw that one coming.”

Wainwright passed up an extra day of rest to jump up into the rotation and thus will have one more start Sunday night before the All-Star break.

How much of a break Wainwright will have still is uncertain. He has been voted to the National League All-Star squad but is ambivalent about pitching in the game.

“I don’t know how to make that decision,” said Wainwright, “other than to say if, for some reason, my spot can go to a guy who’s not on the roster, preferably on this team and (Edward) Mujica, I would like to see that happen.

“Of course I want to pitch in the game but I don’t want to be a liability in any way (like) if I have a pitch count of 12 pitches in one inning. I’d rather see a guy go who really deserves to be there that’s not there.

“What a tremendous honor it would be to pitch in the game (Wainwright has one previous appearance), but if ‘Muji’ could go, I would love to see him take that spot. Let’s put some pressure on them.”

Next Tuesday’s game technically would fall on Wainwright’s “bullpen day,” meaning he would throw a side session between starts. But, normally, Wainwright exerts very little effort in those stints, preserving “all my bullets” for the games.

“If I’m going to pitch 250 innings, which I feel like I want to do, I want to have some bullets saved up,” he said.