HOUSTON (AP) -- Brandon Backe struck out six in seven effective innings, Ty Wigginton drove in three runs and the Houston Astros won their fifth straight game, beating the San Francisco Giants 3-1 on Monday night.

Jose Valverde shut out the Giants in the ninth for his 29th save after LaTroy Hawkins pitched a perfect eighth for the Astros, who've won nine of their last 11. Houston has won five in a row for the first time since May 2-7.

Backe (7-11) allowed a run and four hits to win for just the third time in eight starts. He rebounded from his worst start of the season, when he gave up 11 runs in 3 1-3 innings against the Chicago Cubs last Wednesday.

Jonathan Sanchez (8-9) didn't allow a hit for five innings, but again got no support from San Francisco's bats. The Giants have scored one run or less during 12 of his 24 appearances this season.

Humberto Quintero led off the Houston sixth with a broken-bat single just over shortstop Ivan Ochoa. Backe beat out a bunt that got past Sanchez and Kaz Matsui advanced the runners with a sacrifice bunt.

Wigginton then singled to center field to give Houston a 2-1 lead.

Backe walked Rich Aurilia with one out in the seventh, but Emmanuel Burriss hit a hard grounder back to the mound to start a double play. Backe pumped his fist as he ran back to the dugout.

Hawkins set down the Giants in order in the eighth, striking out two of the three batters. Wigginton hit a solo homer to left off Billy Sadler in the Astros' eighth.

The Giants won their last two games after trailing in the ninth inning, but Valverde made sure that didn't happen this time.

He struck out Fred Lewis, got Bengie Molina on a groundout and fanned Aaron Rowand to end it.

Backe walked two in the first inning, but didn't allow a run, a rarity for him. He came into the game with a 7.88 ERA in the first inning this season and a 4.51 ERA in the rest of games.

But the Giants took a 1-0 lead in the third after Ochoa doubled and scored on Lewis' single to left. Wigginton bobbled the ball as Ochoa rounded third and his throw home was late. Wigginton made his

first start of the season in left field in place of Carlos Lee, who's out 6-to-8 weeks with a broken left little finger. Lee had surgery earlier Monday.

Sanchez retired the first eight batters he faced, then walked Backe with two outs in the Houston third. Matsui flew out to end the inning.

The Astros went down in order again in the fourth. Sanchez retired seven of the first 12 Houston hitters faced on groundouts.

Mark Loretta and Hunter Pence flew out to start the Astros' fifth and Sanchez fanned Michael Bourn for his first strikeout.

Notes:@ Sanchez has lost his last five decisions and San Francisco has lost in his last seven starts. ... Wigginton has 12 homers this season and 21 RBIs in his last 26 games with an at-bat. ... Before the game, the Astros honored Bill Blair, a former pitcher in the Negro Leagues.