ST. LOUIS -- On a night when the Giants knocked out the major league ERA leader in the fifth inning, had Hunter Pence crush a homer into Mark McGwire territory and got 10 strikeouts from their young ace, the most impressive moment might have been a walk.

Brandon Hicks fouled off four Adam Wainwright pitches before taking a 10-pitch walk with two outs and none on in the second. It was the kind of plate appearance that has become emblematic of the grinding Giants, and it opened the floodgates in an impressive 9-4 win over the St. Louis Cardinals. The Giants scored four runs in the inning -- three coming on Pence's blast -- and Wainwright wouldn't last much longer.

"That was big," a beaming Pence said of the walk. "When you're facing a guy like Wainwright, you try to fight and scratch and claw to get the pitch count up. He's one of the best in the game. That (plate appearance) was pivotal to that inning."

Pence's homer gave the Giants a 5-0 lead, stunning and silencing a rowdy crowd at Busch Stadium. Madison Bumgarner kept them quiet the rest of the night, allowing just four base runners in seven shutout innings and erasing two of them with double plays. He has back-to-back 10-strikeout games for the first time since 2011.

"You know you've got to be on it and geared for a 1-0 game," Bumgarner said of the marquee pitching matchup. "Fortunately for us, (Wainwright) didn't have it tonight."

That was clear from the outset, a leadoff double by Angel Pagan. Michael Morse put an early run across with a two-out single in the first, and Wainwright soon joined the rest of the National League pitchers who have found out that the Giants do their best work without breathing room. The Giants entered the night with a majors-leading 110 runs with two outs and scored their first seven runs Friday with two-out hits.

"It's hard to explain these things," manager Bruce Bochy said. "In the past, we've had trouble with that, but now we've been on a roll with two-out hits. That's how you win games."

The second-inning rally was one of the most impressive yet. After Wainwright got two quick outs, Hicks fell behind 0-2 but hung in until he was sent to first.

"I was just in battle mode," he said.

Bumgarner followed with a single to left, and Pagan singled up the middle, scoring Hicks and giving the Giants a 2-0 lead. Pence jumped on a hanging curveball, hitting it into the third deck in left field, an area with a "Big Mac Land" sign made famous by McGwire's marches toward home run history. Wainwright took the mound with a 1.67 ERA but gave up seven earned in 41/3 innings.

"The offense did an unbelievable job," Bumgarner said. "Scoring runs off someone like that is pretty special."

Everything about the Giants qualifies as pretty special at the moment. They've won 8 of 9 and improved to 17-10 on the road. They've earned at least a split of a four-game set with a team that's one of the standard-bearers in the National League. The Giants breathe that rare air, too, and this year's club looks as good as either of the two championship teams. The streaking Giants aren't getting cocky, though.

"Me and everyone else in here know how quickly it can turn," Bumgarner said. "So we're enjoying it right now."

  • Right-hander Matt Cain will go on the disabled list Saturday morning because of a right hamstring strain that took him off the mound May 21 at Coors Field. Cain hasn't pitched since but had hoped to return to the rotation Saturday. The training staff and management opted for a more cautious approach.

    "It's a few more days to where we'd really be convinced he was 100 percent," Bochy said. "We just at this point don't think it's worth the risk. We don't want to put him in a situation where he's at risk of reinjuring this."

    Cain is scheduled to come off the D.L. on June 6, when he would start the first of a 10-game homestand. Yusmeiro Petit started in place of Cain on Monday and will take his spot Saturday. Outfielder Juan Perez will be recalled from Triple-A Fresno to take the open roster spot.

  • Nerve irritation in Buster Posey's lower back kept him out of the starting lineup for the second straight game and fourth time in the past 11 games.

  • Pablo Sandoval extended his hitting streak to 10 games, but his RBI streak ended at nine.

    For more on the Giants, see Alex Pavlovic's Giants Extra blog at blogs.mercurynews.com/Giants. Follow him on Twitter at twitter.com/AlexPavlovic.

    SATURDAY'S GAME
    Giants
    (Yusmeiro Petit 3-2)
    at St. Louis (Michael Wacha 3-3),
    11:15 a.m. CSNBA