HOUSTON — Roy Oswalt allowed three hits in seven crisp innings and the Houston Astros handed the Arizona Diamondbacks their sixth straight loss with a 1-0 victory on Friday night.
Oswalt (7-4) improved to 9-1 in 11 career starts against the Diamondbacks, including a 7-0 mark in seven starts at Minute Maid Park. Jeff Keppinger drove in the only run for the Astros, who have won four of five.
LaTroy Hawkins pitched the eighth and Jose Valverde finished the four-hitter for his 19th save in 23 chances this season and third in three games.
Yusmeiro Petit (2-8) lost for the fifth time in seven starts, though he almost matched Oswalt pitch for pitch. Petit allowed four hits in six innings after giving up a total of 10 earned runs in his previous two starts.
The Diamondbacks were shut out for the eighth time this season and have lost their last eight road games.
Houston went in front in the fifth. Hunter Pence walked with one out and stole second as Keppinger batted. Keppinger drove the next pitch off the left-field scoreboard and Pence scored easily.
Keppinger started at second base in place of Kaz Matsui, who's in a 1-for-25 slump.
Arizona put runners on first and second with no outs in the third but couldn't come up with a clutch hit. First baseman Lance Berkman made a nice play on Petit's sacrifice attempt, racing in and throwing to third to retire the lead runner. Stephen Drew grounded out before Oswalt struck out Gerardo Parra.
Petit retired the first 11 hitters he faced, four on strikeouts. Berkman beat out a slow roller to third baseman Mark Reynolds for Houston's first hit, but Carlos Lee popped out to end the inning.
Petit escaped a bases-loaded jam in the sixth when Geoff Blum and Pence popped up.
Oswalt allowed only one hit in his last four innings, though two hitters reached base on errors by Houston infielders. He threw 100 pitches and didn't walk a hitter for the fourth time in 25 starts this season.
Hawkins relieved Oswalt and pitched a perfect inning, striking out the last two hitters he faced. Hawkins has not allowed a run in five appearances since coming off the disabled list on Aug. 12 after treatment for shingles.
NOTES: The Astros have committed errors in three straight games. ... The Astros are 8-1 in the last nine games Oswalt has started. ... Arizona manager A.J. Hinch met with his starting pitchers on Friday after the Diamondbacks were outscored 25-5 in three games in Philadelphia. "I really just wanted to regain our mindset as to making the most out of our last six weeks of the season," Hinch said. "The last thing I want is the start of any sort of demoralizing attitude or frustration to set in." ... The Diamondbacks arrived at their hotel in Houston about 3 a.m. on Friday and had to wait more than an hour to get to their rooms because of a chlorine leak in the hotel's pool.