The Astros faced the Braves in the playoffs for the fourth time in Bagwell's career in the 2004 NLDS. In Game 3, on October 7, he hit his first career postseason home run off Mike Hampton in the first inning in a 4–2 extra-inning loss. After three failed attempts to advance past the first round of the playoffs earlier in Bagwell's career – all to the Braves (1997, 1999, and 2001) – and seven overall in 43 years of franchise history, the Astros defeated the Braves for their first-ever playoff series win. The quartet dubbed the "Killer B's" – this time with the additions of Carlos Beltrán and Lance Berkman – ignited the Astros' offense, batting .395 (34-for-86) with eight home runs, 21 RBI and 24 runs scored. The Astros scored an NLDS-record 36 runs in all and Bagwell batted .318 with two home runs and five RBI. They advanced to Bagwell's first National League Championship Series (NLCS) to face the Cardinals. St. Louis defeated Houston in seven games to advance to the World Series.