Pittsburgh, PA – The Steelers didn't need Big Ben to beat the down defense was more than enough.
The playoff-bound Steelers (11-4) also got rushing touchdowns from John Clay and Isaac Redman, bouncing back from a loss to San Francisco on Monday to win for the fifth time in six games.
Despite playing without Roethlisberger, who was finally sidelined by a high ankle sprain he suffered two weeks ago, Pittsburgh locked up a 7-1 home record for the season.
Batch had thrown just two passes this season before Saturday, but was 15-of-22 for 208 yards with an interception, hitting seven receivers in the win.
St. Louis has lost six games in a row since its last win November 13 over Cleveland.