HOUSTON -- The Giants were reminded Wednesday night that every man with a bat in his hands is dangerous, regardless of how he wielded that stick in the past.

Giants left-hander Barry Zito didn't figure to face much of a challenge from his Houston counterpart, Brett Myers. But instead of swinging the bat as most pitchers do -- meekly and ineffectively -- Myers rapped singles in his first two plate appearances that helped the Astros top the Giants, 6-3.

Myers' hits contributed to the 5-0 lead Houston built through four innings against Zito. Equally annoying to the Giants was the fact that the Astros scored all of those runs with two outs, including the first four after having two outs and nobody on base.

"That did us in, really, especially the second inning," said Giants manager Bruce Bochy, referring to Houston's three-run uprising.

The Astros needed Myers' rare hits to end San Francisco's nine-game winning streak against them dating back to last year. Because the Giants, as is their custom, remained competitive. They brought the potential go-ahead run to the plate in the fifth inning and had the possible tying run at bat in the eighth.

Ultimately, the evening galled the Giants in all facets. Zito (7-4) lasted only four innings, his shortest outing of the season, and San Francisco mustered three runs at hitter-friendly Minute Maid Park for the second game in a row.

Scoring wasn't a problem for the Astros. Lance Berkman prolonged the first inning with a ground-rule double and came home on Carlos Lee's single.

Jeff Keppinger's bases-loaded double accounted for Houston's second-inning runs. That hit was preceded by a pair of lapses by Zito: a walk to eighth-place hitter Jason Castro and Myers' first hit, a bloop to left field.

With his broken-bat RBI single in the fourth inning, Myers doubled his season hit total in this game alone. He entered Wednesday batting .038 (1-for-26). Myers also owned a .116 lifetime average (43-for-372) with 126 strikeouts in 439 plate appearances.

"A squirrel finds his nut every now and then," Myers said. "I guess I got lucky."

Zito called Myers' singles the difference in the outcome, yet didn't second-guess the deliveries that were hit: first a changeup, then a slider.

"It's really frustrating, but at the same time, I'd probably throw those same two pitches again because they weren't such bad pitches," Zito said. "They missed the barrel [of the bat] both times."

Zito acknowledged Myers' microscopic batting average but added, "He's actually one of the tougher outs as a pitcher. He's on the offspeed stuff a lot more than most pitchers in the league."

Asked if he thought Zito's concentration waned against Myers, Bochy said, "I don't think it was a lack of concentration as much as he wasn't getting the ball where he wanted tonight."

Pablo Sandoval didn't quite get the ball where he wanted, either. After Andres Torres lined an RBI triple and scored in the fifth inning to trim Houston's lead to 5-2, the Giants loaded the bases with two outs. Sandoval ended the inning with a drive to the warning track in a recessed portion of left field. Had the ball traveled about 20 feet toward the left-field line, it would have at least caromed off the wall in front of the Crawford boxes and might even have carried into the seats for a grand slam.

Sandoval swung at Myers' first-pitch slider, but did so with good reason.

"It was the pitch I was looking for," Sandoval said.

One-out singles by Edgar Renteria and Bengie Molina roused the Giants again in the eighth. Astros reliever Brandon Lyon responded by retiring pinch-hitter Nate Schierholtz on a popup and striking out Torres.

"We were fighting to get back in it," Bochy said after the Giants stranded 10 baserunners, including seven in scoring position. "We were just missing a hit."