Patrick Hornqvist and Brandon Sutter also scored for the Penguins, who snapped a three-game skid. Sidney Crosby got his 40th assist on Hornqvist's goal.
Pittsburgh is 12-4-2 against Western Conference teams and 5-1-1 in its last seven road games.
Playing in place of starter Marc-Andre Fleury, backup goalie Thomas Greiss proved up to the challenge. Greiss stopped 21 shots and had the Blues shut out until giving up a goal to Dmitrij Jaskin with 5:27 left.
Introducing the new official NHL App, available for iPhone, iPad and Android smartphones and tablets. A host of new features and improved functionality are available across all platforms, including a redesigned league-wide scoreboard, expanded news coverage, searchable video highlights, individual team experiences* and more. The new NHL App on your tablet also introduces new offerings such as 60fps video, Multitasking** and Picture-in-Picture.
*Available only for smartphones
** Available only for suported iPads