SAN FRANCISCO -- Tim Lincecum continued to turn potential into results Tuesday night in the San Francisco Giants' 4-2 victory over the Houston Astros.

With each outing, Lincecum takes a step forward into his seemingly bright future. In his Major League debut, he struck out the side in the first inning. Next time out, he recorded his first victory. Last Thursday in Houston, he struck out 10 in seven innings.

Lincecum outdid himself this time by pitching eight innings, his most as a Giant, while surrendering five hits and both Astros runs. Although his four-strikeout total was the lowest among his four starts, he demonstrated his polish by lasting as long as he did on 104 pitches. Lincecum's 15 ground-ball outs reflected his capacity for craftsmanship.

"Each outing, he's done a better job of pitching," manager Bruce Bochy said after the Giants' third consecutive victory. "He's not just throwing out there."

"I like strikeouts," Lincecum admitted. "I try to get strikeouts, but when it doesn't work that way, I'm going to keep pitching the way that they're going to get themselves out."

The Giants also learned more about Lincecum's poise, which Bochy called "very impressive." Matched against Roy Oswalt for the second time in a row, Lincecum (2-0) ignored the challenge of facing the Astros ace, survived a rocky fourth inning and, except for that inning, allowed just two runners to reach base.

"Growing up when I was an early teenager and my dad was coaching, I wouldn't get a call [from an umpire] and I'd throw my arms up," Lincecum recalled. "But he taught me that's the way things are going to go sometimes; you have to accept it. I feel like my poise might be the strongest part of my game. I don't show how things get to me."

Make no mistake -- Lincecum often looked overwhelming with his 97 mph fastball and parabolic curveball.

"When he has that breaking ball working, it's going to be tough for those guys to stay on his fastball, and that's what he had again," Giants first baseman Ryan Klesko said. The paid crowd of 35,134 at AT&T Park noticed, as they proved by showering a standing ovation upon Lincecum as he left the mound following his final inning.

"You can't really tell right now, but I'm probably going to be excited a little later," Lincecum said of his first home win. Of the fans' ovation, he remarked, "That helped make me feel I belonged here and am part of the team."

As good as Lincecum was, Oswalt (6-3) was better for much of the game. The perennial Cy Young Award candidate retired the first 10 hitters he faced (Lincecum retired the first nine) and held a 2-1 lead entering the sixth inning, when the Giants scored three runs.

Ordinarily, the Giants could rely on Barry Bonds to rescue them with one swing. But the left fielder continued to slump, going 0-for-2 with two intentional walks to extend his homerless streak to 12 games. Bonds is batting .152 (5-for-33) in that span, prompting Bochy to announce that he'll rest the cleanup hitter Wednesday.

Moreover, Randy Winn went 0-for-4, halting his hitting streak at 20 games. Yet the Giants mustered enough offense to survive. Klesko was a presence for the second night in a row, going 3-for-4 and helping generate both of the Giants' scoring rallies. Ray Durham and Pedro Feliz drove in a pair of runs apiece.

"It's not just one guy hurting you," Durham said. "When you get different guys in the lineup getting big hits, you can't pitch around one guy. The next guy may get you. Last night they pitched around Barry, and I couldn't get the job done, but Bengie [Molina] came through."

Durham was referring to the Giants' big sixth, when five consecutive batters reached base safely with one out. Klesko drilled his second double of the evening and Bonds drew an intentional walk. After fouling off a pair of 1-2 pitches, Durham grounded a fastball into right field for a single, scoring Klesko.

"He pitched me tough -- a back-door slider, sinkers away," Durham said of Oswalt. "I finally got something I could drive to the outfield."

Molina's single loaded the bases before Feliz doubled into the left-field corner on an 0-1 fastball, scoring Bonds and Durham.

After Lincecum no-hit Houston in his final three innings, the Giants received a mild scare in the ninth when Carlos Lee followed Lance Berkman's leadoff single with a drive to deep left-center field off Armando Benitez. But Winn hauled in the ball a few paces in front of the 404-foot marker, freeing Benitez to retire the next two hitters for his ninth save in 10 chances.