Carl Gunnarsson scored the game-winning goal Monday night in a 4-2 victory over the Los Angeles Kings.
Vladimir Tarasenko and Jaden Schwartz each had a goal and an assist to lead the Blues in a matchup between two of the NHL's top squads, Vladimir Sobotka added an empty-netter for the Blues, who improved to 10-2-1 to match the franchise's best start set in 1997.
Jake Allen made 26 saves as St. Louis remained the only unbeaten team on home ice this season (5-0).
Tanner Pearson and Dustin Brown scored for the Kings, who had their three-game winning streak snapped and fell to 9-2-1. Jonathan Quick made 26 saves.
Tarasenko and Schwartz continued their strong play against Los Angeles. Tarasenko has 14 points in 15 career games and Schwartz has six points in his last five games against the Kings.
Tarasenko gave the Blues a 1-0 lead and broke a five-game goal drought at 7:25 of the second period. Schwartz picked off Derek Forbort's pass at center ice and found Tarasenko streaking in on the left side.
Three minutes later, Schwartz cleaned up the rebound of Brayden Schenn's shot to make it 2-0.
Allen robbed Pearson with a glove save after Pearson found himself alone in front with 7:52 left in the second.
Pearson made good on his second chance, putting a backhand past Allen with 6:40 left in the second after he got behind Gunnarsson for a breakaway to cut the St. Louis lead to 2-1.
The Blues host the Philadelphia Flyers on Thursday.