Webb (18-4) allowed two runs and four hits, striking out six batters. He has won five straight starts.

Chris Snyder slugged a two-run home run and drove in four runs, Chris Burke hit a three-run homer and Chris Young added a solo shot for the Diamondbacks.

Loser Wandy Rodriguez (7-5) allowed six walks and gave up four runs and three hits in 2 1/3 innings.

Astros' reliever Tim Byrdak was tagged for six runs, including all three Arizona homers, in three innings.

Ty Wigginton hit a solo homer for Houston.