It hasn't been the best week so far for the defending champion San Francisco Giants. Perhaps a visit to Houston to take on an Astros club that sports the worst record in baseball can lift their spirits.

Or at least their offense.

Hoping to continue last year's domination of the club, San Francisco begins a three-game series with Houston tonight at Minute Maid Park.

The Giants began the week with a chance to put some more pressure on the National League West-leading Diamondbacks and close the gap a bit with the current holders of the wild card position, the Braves.

However, San Francisco lost three of four in Atlanta, all by just one run, and fell six games behind the Braves for the league's final playoff spot. It also sits 2 1/2 games back of the Diamondbacks in the division standings.

The Giants had their ace on the hill for Thursday's finale and Tim Lincecum pitched like they needed him to. The two-time NL Cy Young Award winner yielded just one run and struck out seven over seven innings of work, but suffered a 1-0 setback.

The lone run of the game came on Chipper Jones' fifth-inning homer and the San Francisco offense had no response.

"Just one big mistake that I made with that pitch and he hit it out of the park," Lincecum said. "I have a knack for doing that, giving up that go-ahead home run. If I could just eliminate that, whatever game I'm in at that time, sure we'd be a lot more successful."

The Giants remained without closer Brian Wilson, who is day-to-day with right elbow inflammation, while in-season acquisition Carlos Beltran is currently taking up residence on the disabled list due to a strained right wrist.

San Francisco may be able to get by without those key players if it can duplicate recent success in this series. The Giants won nine in a row over the Astros, including the first seven meetings of last year, before the Astros closed out the season set with consecutive wins at home in late June of 2010.

Houston will be looking to win three straight overall for the first time since a four-game win streak from May 30-June 2 after winning its final two meetings with Chicago. That includes Wednesday's 4-3 triumph in the rubber match.

Matt Downs had two hits and drove in a pair of runs, while Brian Bogusevic added a two-run double. Houston had lost seven in a row before this current win streak, which Bud Norris helped extend by giving up three runs over five innings.

"I didn't have my best stuff today. I'm just trying to battle, especially this late in the season," said Norris. "I was happy to get through five."

The Astros' Wandy Rodriguez looks to get back to the .500 mark tonight after losing for the fifth time in seven decisions last time out.

The left-hander was defeated by the Dodgers on Saturday as he was charged with five runs. Just two of those were earned and he also yielded six hits and two walks over six innings of a 6-1 defeat that dropped Rodriguez to 8-9 with a 3.50 earned run average in 22 games.

The 32-year-old Rodriguez will make his fourth career start against the Giants and is 1-2 with a 5.17 ERA in this series.

The Giants turn to All-Star Ryan Vogelsong.

After suffering just his second loss of the season and first in 12 starts on Aug. 8 versus the Pirates, Vogelsong quickly bounced back into the win column by besting the Marlins on Sunday. He allowed a pair of runs on four hits and two walks while striking out eight over 7 2/3 innings.

The right-hander moved to 10-2 with a 2.47 ERA in 22 games this year, all but two of those starts, and is 4-0 on the road this season.

Vogelsong, 34, is 2-0 with a 2.51 ERA in his career versus the Astros, spanning nine outings and two starts.