SAN FRANCISCO -- Miguel Tejada is going to have the day off Thursday, and deservedly so. The shortstop has played in every game so far, while all of his teammates have had at the very least one day of rest at some point this season.

Manager Cecil Cooper has been trying to find a good time to give his slugger a breather, but that's not easy to do, considering what Tejada brings to the lineup. On Wednesday, he further proved his value to this club, driving in the go-ahead run as the Astros topped the Giants, 6-3, before 33,070 fans at AT&T Park.

Facing Giants righty Billy Sadler with the game tied at 3 and two outs in the seventh, Tejada knocked a 1-2 fastball up the middle, scoring Jose Cruz Jr. from second. Cruz had led off the frame with a pinch-walk and advanced to second on Michael Bourn's sacrifice bunt.

"I knew he was going to get a hit right there," Cooper said. "I just felt it. You don't get through that guy; you don't throw fastballs by that guy two or three times in a row. I actually said, 'He's trying to sneak some cheese by the rat.' You don't sneak cheese by guys that hit the fastball."

Tejada was 3-for-5 on the night, improving his season batting average to .345. He owns a seven-game hitting streak, during which he's hitting .414 (12-for-29).

And he's not playing Thursday.

"We've been talking about this for over a week, about doing it," Cooper said. "I asked him to pick a day. He said, 'I'll let you know.' That's what they all kind of say -- 'I'll let you know.'

"He never wants to come out. And before tomorrow's over, he might be in there. We'll try not to use him, but he might be in there. Let's put it this way. He's not starting."

Said Tejada: "When you're having the year I'm having now, you don't want to be out of the game. But I think it's good because it gives other players some playing time. I'm going to enjoy it. But I'm going to be ready in case he needs me at any moment."

Fortunately for the Astros, they have myriad hitters who have come through in the clutch this year. Lance Berkman predictably went deep, pushing the Astros ahead, 3-0, with a two-run homer off Pat Misch in the opening frame. That homer extended his hitting streak to 13 games, during which he's hitting .560.

Carlos Lee contributed one hit and Hunter Pence two, but it was Brad Ausmus' towering shot to left that had the Astros' dugout buzzing. Ausmus launched a two-run shot off Sadler in the eighth, creating a much more comfortable three-run cushion as the Astros pushed toward their fifth win of the road trip.

"Holy cow, we got two more runs," Cooper said. "He put a good swing on it. The ball was up in the strike zone, a fastball, I think it was. Brad has a little power. He can do that once in a while."

Every once in a long while. It was Ausmus' first homer of the season and his first since last Aug. 8, spanning 121 at-bats.

"As a catcher, you're trying to work with pitchers and get a win," Ausmus said. "A three-run cushion with a couple innings to go is greatly preferable to a one-run lead. In that sense, it was a big two runs."

Ausmus received the rookie silent treatment upon retreating back to the dugout, where not a single teammate offered a congratulatory high-five. He quietly sat down on the bench and suited up in his catcher's gear and after a few moments was besieged by his laughing teammates.

"He's usually the one who's playing the jokes," Tejada said. "Now we all got him. It's good for a guy like him to have a big home run like that."

"As soon as I stepped in, I knew what they were doing," Ausmus said. "This is a good group of guys. They're a lot of fun. It's just another example of the lightheartedness of this team as a group. They have fun."

Ausmus is good-natured about his lack of hitting prowess and laughs off the frequent jokes on the subject at his expense. But he also takes that side of the game seriously, even if he doesn't always produce great results.

"I certainly put more time into my hitting than any other aspect of my game," he said. "Unfortunately for me, there's not a direct relation between hard work and batting average. Some people are just more gifted hitters naturally or they have more power naturally. Like Lance."

"We can't all be smart and good looking like Brad," Berkman offered.

Brian Moehler yielded three runs in the second, which tied the game at 3. Moehler gave up a two-run homer to Aaron Rowand, and the Giants scored again when a play at the plate went awry following a Misch bunt. Moehler threw home in an attempt to nab John Bowker, but Ausmus missed the catch.

The botched play appeared to be Ausmus' fault, but Moehler was charged with the error.

"It should be my error," Ausmus said. "I told [Moehler] it seems like it went in a time warp and disappeared, because I never saw it."