Ryan Howard belted a three-run homer and Roy Halladay retired the last 21 batters he faced as the Philadelphia Phillies erupted for an 11-6 home triumph over the St. Louis Cardinals on Saturday in Game 1 of their National League Division Series.

Raul Ibanez capped a five-run sixth inning with a two-run blast and Shane Victorino added a pair of RBI singles for NL East champion Philadelphia, which hosts Game 2 at Citizens Bank Park on Sunday night.

Hunter Pence finished the scoring with a two-run single for the Phillies, who plated 10 runs on 12 hits over their final three innings.

With St. Louis clinging to a 3-1 lead in the sixth, Howard finished off an eight-pitch at-bat by depositing a changeup from Kyle Lohse (0-1) into the second deck in right-center field.

After Victorino reached base with his second single of the game, Ibanez sent another hanging changeup into the seats to give the Phillies a 6-1 lead.

Halladay (1-0) yielded a three-run homer to Lance Berkman in the first inning before settling down. The reigning NL Cy Young Award winner did not allow another hit after Skip Schumaker singled to lead off the second. Halladay allowed three runs on as many hits in eight innings.

Schumaker added a two-run single to highlight a three-run ninth for St. Louis, which won 23 of its last 32 to secure the wild card on the last day of the season.

Lohse permitted six runs on seven hits in 5 1/3 innings.