HOUSTON -- With their pitching, the San Francisco Giants figure if they can get about three runs a game they should win on most days.
On Wednesday, they blew right past that mark, beating the Houston Astros 10-4 to complete a season-opening three-game sweep.
Edgar Renteria tied a career high with five hits to help the Giants to a 3-0 record for the first time since 2003, when they began with a sweep at San Diego and won seven straight. Houston last started 0-3 in 2007.
"When you come to the ballpark every day and feel like you've got a really good opportunity to win some games because of the guy who's on the hill, that's a good feeling," said Aaron Rowand, who had four of the Giants' 19 hits. "That's a confidence-builder in itself."
It was 4-all when Juan Uribe doubled in the eighth inning and scored the go-ahead run when Sammy Gervacio (0-1) threw away a bunt. The Giants added another run in the inning, then scored four times in the ninth.
"With the way these guys were swinging in spring it gives us a bunch of confidence out there on the mound that if we give up a couple of runs like we did out there today ... those guys can come right back to pick us up," Cain said. "That builds a lot of confidence for the starters and the relievers and I think it builds confidence for those guys as well."
Astros starter Brett Myers gave up a career-high 12 hits and four runs in six-plus innings in his Astros debut.
"I felt like it was a battle from the first inning on," he said. "I had to pitch certain ways that I'm not used to throwing. But you've got to make an adjustment when they're getting that many hits off you."
Rowand, the Giants' leadoff man, and Renteria, the No. 2 hitter, each drove in two runs.
"He's swung the bat well all series and what a day he had today," Bochy said of Renteria. "It's hard to play this game when you're hurt and I said that last year. He's healthy now and he has a good approach up there. It was a great game by him."
The 34-year-old said he's feeling "great" this season after playing just 124 games last season because of shoulder and elbow problems.
"When you feel better, you relax and play the game," he said. "You don't have to worry about pain or nothing."
Uribe made it 5-4 when he scooted home after Gervacio overthrew third base on a sacrifice by Eli Whiteside. Rowand had an RBI single later in the eighth.
Uribe hit an RBI double to highlight the ninth.
The Astros scored three runs in the seventh that made it 4-all. Pinch-hitter Cory Sullivan hit a two-out, two-run triple that Rowand bobbled before dropping near the hill in center field. That finished Cain, and the speedy Michael Bourn tied it when he barely beat the throw on a single off Affeldt.
"We knew it was going to be tough going in anyway with the pitching we were going to be facing," Astros manager Brad Mills said. "But it was good to see us battle back at least today."
Rowand tripled in the seventh inning when both Bourn and Hunter Pence had trouble scooping up the ball. Renteria drove him in with a single that made it 4-1 and chased Myers.
Bourn is optimistic that the Astros will get on track in their next series which starts Friday against the Phillies.
"We know not to panic and we know we have a good group of guys that can get clicking at any time," he said. "We'll just wait on that point and hopefully it will start Friday."
Bowker's two-run homer that landed in the bullpen in right-center field in the second. It was his first career hit against Myers after striking out in his previous three at-bats against him.
The Giants pushed the lead to 3-0 in the third when Renteria scored as Mark DeRosa grounded into a double play.
Pedro Feliz doubled twice for the Astros, including an RBI hit in the fourth.
Wednesday was the 10th anniversary of the opening of Minute Maid Park, then known as Enron Field. Houston lost that game 4-1 to the Phillies. ... Giants OF Fred Lewis, on the disabled list with a ribcage injury, will begin a rehabilitation assignment on Thursday with Triple-A Fresno. ... Gervacio injured his shoulder in the eighth inning and was placed on the 15-day disabled list after the game. Houston recalled RHP Wilton Lopez from Triple-A Round Rock to take his roster spot.