SAN FRANCISCO — Matt Cain didn't mind while Tim Lincecum graced magazine covers, shot quirky commercials, won Cy Young Awards and made a city swoon.

The mule-strong kid from Memphis was content to sit at the opposite end of the Giants' clubhouse, quietly picking his guitar and putting on his work apron every fifth day.

But now Lincecum is searching to find himself after three wild outings. And amid those unsettling thoughts, Cain stood tall to stabilize the club Friday night.

Cain pitched one of the finest games of his career, dominating the Arizona Diamondbacks while throwing a one-hitter in the Giants' 5-0 victory at AT&T Park.

Cain (3-4) allowed only two baserunners. Mark Reynolds doubled over the reach of right fielder Nate Schierholtz in the second inning; Reynolds was hit by a pitch in the fifth.

Cain threw a fusillade of strikes, attacking a lineup that abused Giants pitchers last week at Chase Field. Arizona had scored 21 runs while sweeping that two-game series; it entered Friday night as the highest-scoring team in the National League.

Even as Cain's pitch count climbed into triple digits, the Giants bullpen remained still, its mounds undisturbed by a single cleat mark. Cain struck out nine, didn't walk a batter and extended a streak of 19 innings without an earned run.

It was Cain's second career one-hitter. His previous one came May 21, 2006, at Oakland.

And after second baseman Freddy Sanchez gobbled up the final out, Cain simply walked toward catcher Bengie Molina to offer a handshake.

Lincecum might be the heart of this team, but Cain has plenty of soul. He's also the longest-tenured player on the club, a fact often lost because he's still just 25.

When Molina staggered underneath Adam LaRoche's foul pop in the seventh inning, Cain calmly held up his glove for another ball and struck out the power hitter on the next pitch.

It would have taken a brilliant play on Reynolds to remove the only hit from Cain's record. Schierholtz raced back and banged against the bricks, but the ball sailed just out of his reach.

Sanchez was the Giants' offensive difference-maker for the second consecutive game. A day after his two-run single capped a comeback against the Washington Nationals, Sanchez reached base in each of his first three plate appearances while contributing to the first three run-scoring rallies.

Sanchez's single off Edwin Jackson in the first inning scored Andres Torres, who had hit a leadoff double. Sanchez doubled in the third to set up Pablo Sandoval's sacrifice fly, which scored Cain.

And Sanchez's two-out walk extended the fifth inning for Sandoval, who stayed back while lining a run-scoring single.

Sandoval's swing already looked improved and balanced before the eighth, when he broke a streak of 124 at-bats without a home run. His solo shot off Chad Qualls slipped over the center-field fence; it was his first since April 21 off San Diego's Edward Mujica.

But the bottom half of the order remained unproductive. Molina was hitless again and extended his streak to 19 games without an RBI. He's hitting .203 in May.

Aaron Rowand hit a deep fly ball to the warning track for a sacrifice fly but went 0 for 3 to deepen a slump in which he's hitting .130 over his past 17 games.

The Giants continue to look at alternatives. Notably, catcher Buster Posey started at first base for the second consecutive game at Fresno, and GM Brian Sabean told KNBR that club officials have discussed promoting him to play the position. Sabean personally scouted Posey last week and told KNBR that "the kid's really improving."

Added Sabean: "But when we bring him here, we want to make sure he's on the field at least five days a week."