The Dodgers tie a post-1900 major league record with their 12th straight win at home to open the season when they beat Arizona, 3 – 1. Detroit is the only other team to win its first twelve games at home, in 1911. Jeff Weaver picks up his first victory since 2007 for the Dodgers.

On May 5, 2009 — The Dodgers tie a post-1900 major league record with their 12th straight win at home to open the season when they beat Arizona, 3 – 1. Detroit is the only other team to win its first twelve games at home, in 1911. Jeff Weaver picks up his first victory since 2007 for the Dodgers.

Source:
Baseball Reference May 5