Tim Lincecum pitched seven scoreless innings as the San Francisco Giants beat the Houston Astros 5-2 on Monday night.

Lincecum (1-0) allowed four hits and struck out seven with no walks to shut down a Houston offense that started the season with star slugger Lance Berkman on the disabled list.

The Giants got a boost from new left fielder Mark DeRosa, who scored in San Francisco's three-run second inning and added a solo homer in the eighth.

Houston starter Roy Oswalt (0-1) allowed seven hits and three runs in six innings as he extended his team record to eight straight Opening Day starts.

Giants reliever Sergio Romo allowed two hits in a scoreless eighth inning, but Houston finally got on the board in the ninth when Carlos Lee singled and scored on a groundout by Pedro Feliz. Then J.R. Towles followed with an RBI double off Brandon Medders.

Brian Wilson came in for the last two outs to register the save.