T.J. Oshie and Kevin Shattenkirk each had a 1.
The Blues went 4-0 against the Sharks this year to sweep the season series for the first time since taking all four meetings during the 1994-95 season.
Andy McDonald also lit the lamp for the Blues, who jumped into a tie with idle Detroit for first place in the Central Division.
Jaroslav Halak made 18 saves for St. Louis, which has won five of six.
Torrey Mitchell scored the lone goal for San Jose, which has lost two straight.
Antti Niemi stopped 29-of-32 shots for the Sharks, who remain two points behind Phoenix for first in the Pacific Division.
McDonald's power-play goal gave the Blues a 1-0 lead at the 2:52 mark of the first period. Shattenkirk dumped the puck into the San Jose zone, and Niemi went behind the net to play the puck. But the disc took an odd bounce off the backboards and ended up in front of an empty net for McDonald.
The Sharks tied the game with 4:31 left on Mitchell's shot from the top of the left circle.
Just 20 seconds later, Oshie deflected Carlo Colaiacovo's shot from the left point. The change of direction threw off Niemi, who watched the disc go past him.
Shattenkirk's power-play goal at the 12:38 mark of the middle stanza made it 3-1.
Halak made a total of 12 saves over the final two periods to secure the victory.
The Sharks have lost eight of their last 10 games...San Jose forward Logan Couture and defenseman Douglas Murray both returned to the lineup. Couture missed two games due to a lower-body injury, while Murray missed eight games with a fractured throat...Sharks head coach Todd McLellan missed his third straight game with concussion-like symptoms.