Winnipeg opened a 4-2 lead on Trouba's fourth of the season 3:33 into the third. Trouba initially fanned on the shot but the puck went off of Pietrangelo's skate and into the net.
The bad bounce on Trouba's goal was another tough break for Allen, who made his first start since being pulled after allowing four goals on 10 shots on Jan. 19. He was replaced in each of his previous three starts, allowing 10 goals on 36 shots during that span.
Allen received sarcastic cheers from the crowd of 19,483 for routine saves throughout the game.
Steen put St. Louis in front just 3:37 into the game on a shot from the point. It was the first time St. Louis scored the opening goal on home ice since Dec. 15.
Scheifele tied it with 30 seconds left in the first on a give-and-go with Blake Wheeler. It was Scheifele's second goal in two games, and Wheeler's assist gave him 20 points in his last 21 games.
Laine gave the Jets a 2-1 lead 22 seconds into the second period. Laine is on a seven-game point streak, and his 41 points leads all NHL rookies.
After Ehlers scored just seven seconds into Winnipeg's first power play, Tarasenko responded for the Blues with 52 seconds remaining in the second. It was Tarasenko's fifth goal and ninth point in his last seven games against the Jets.
NOTES: The Blues recalled F Ivan Barbashev from their American Hockey League affiliate, the Chicago Wolves. ... Jets F Mathieu Perreault missed his third straight game after taking a slash from Anaheim's Corey Perry on Jan. 23.
Jets: Will travel to Dallas on Thursday.
Blues: Will host Toronto on Thursday.
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