SAN DIEGO -- The stat of the night, besides Craig Biggio's two homers, was that the defending NL champion Houston Astros won consecutive games for the first time in nearly a month.
"We've got to keep grinding it out," said Biggio, whose Astros are third in the NL Central, 7½ games behind St. Louis. "To come back and play better tonight was nice. It's a good start to the road trip."
On Tuesday night, Andy Pettitte outdueled Jake Peavy in a 1-0 Houston win.
Biggio's second homer Wednesday, his 13th, came off Jon Adkins with one out in the ninth. Biggio and Mike Lamb hit back-to-back homers in the sixth off starter Woody Williams.
The Astros have won the first two of the three-game set to capture their first series since winning two of three against the Chicago Cubs from July 3-5. The wins against the Cubs on July 3-4 were the Astros' last consecutive victories, coming at the end of a four-game winning streak.
Brandon Backe threw 7 2/3 strong innings in his third start after a long stay on the disabled list with a sprained right elbow. Backe (2-1) held San Diego to one run and seven hits. He struck out three and walked two.
Backe knows that the Astros would have to go on a tear just to win the wild card.
"It's definitely doable," he said. "Nobody thinks it's impossible. This is a great start for us."
The Padres, who continue to cling to the NL West lead, have scored just two runs in their last 29 innings. They've lost three straight and nine of 14.
Todd Walker had a rough debut for the Padres, committing two throwing errors in his first start at third base since 1997, while with Minnesota. The second error by Walker -- who's played second base the bulk of his career -- came with two outs in the fifth and led to the Astros' first run.
"It's no fun to struggle and I feel sorry for Woody," Walker said. "He threw the ball fairly well tonight and it takes a lot to run out there when you haven't played there in a while. I expect a little more out of myself, but at the same time, it's a very, very difficult thing to do."
The Padres acquired Walker from the Cubs on Monday -- more for his bat than his glove. On his first chance, he charged Biggio's two-hopper but threw way wide of first baseman Adrian Gonzalez. Biggio stole second, but was stranded.
Walker and the Padres weren't as lucky the next inning.
Williams (4-3) had held the Astros hitless and retired 14 of the first 16 batters, including the first two in the fifth. Walker fielded Brad Ausmus' grounder and pulled Gonzalez off the bag with another wide throw. Backe followed with a sharp single to left and Willy Taveras singled up the middle to score Ausmus and make it 1-1.
"You can go out and really work and practice all you want. I felt great, I felt perfect in practice. When the bell rings, it's a different deal," said Walker, who has nine errors this season.
"I'm sure he was a little nervous," manager Bruce Bochy said. "It's going to take a little time. I know it, we know it, and it's not that easy. He's worked hard the last couple of days, but any time you make a change in your position it takes a little time."
Williams got himself into trouble by opening the sixth with walks to Lamb and Morgan Ensberg. Both scored, Lamb on a double play and Ensberg on Adam Everett's single to center to make it 3-1.
Biggio and Lamb connected with two outs in the seventh. It was Lamb's ninth.
Bochy came out to get Williams and also took out Walker in a double switch.
The Astros made it 6-1 in the eighth when Luke Scott hit a leadoff double off Scott Williamson and scored on Preston Wilson's single.
Walker atoned for his first error by hitting a leadoff double in the fourth and scoring San Diego's only run on Khalil Greene's blooper to right-center.
"We're just missing the big hit to get the three or four runs that would make life a lot easier," Bochy said.
Williams allowed five runs, four earned, and six hits in 6 2/3 innings. He struck out four and walked three.
The Astros activated OF Orlando Palmeiro from the bereavement list and optioned INF Eric Bruntlett to Triple-A Round Rock. Palmeiro was placed on the bereavement list July 26, a day after his father died. ... Padres RHP Chan Ho Park is expected to have a transfusion on Thursday to treat intestinal bleeding that led him to lose half his blood volume. The bleeding spontaneously stopped but the Padres aren't sure what caused it. Park was placed on the disabled list on Sunday and is eligible to be activated on Aug. 10.