Patrik Berglund scored the game-winner at 1:12 of overtime, as St. Louis rallied past San Jose, 4-3, at HP Pavilion.
Berglund fought off San Jose defenseman Dan Boyle at the left side of the cage and reached over his opponent to redirect a Barret Jackman shot home to end the contest.
"I don't even really feel that I tipped it in, but, you know, we had a great shift," Berglund said. "We kept the puck in ... trying to just go in front of the net there. Trying to battle and be in the way for something, and [Jackman] takes a good shot. I looked back and it's in the net."
Vladimir Sobotka posted his first career hat trick to account for the remainder of the goals for the Blues, who improved to 2-2-0 on their current five-game road trip which concludes on Sunday in Anaheim.
Jake Allen made 22 saves for the win.
Logan Couture, Scott Gomez and Matt Irwin tallied for the Sharks, who have lost two in a row and three of five.
San Jose goaltender Alex Stalock appeared in his second NHL game and was stuck with the loss after allowing the deciding goal. Starter Antti Niemi was pulled in the third period after giving up three goals on 28 shots.
Sobotka opened the scoring for the visitors just under five minutes after the drop of the puck, potting a Kevin Shattenkirk rebound from the right side
Couture evened things with just under five minutes to play in the frame, slipping a loose puck inside the right post.
Gomez gave the Sharks a one-goal edge at 7:45 of the second period, picking up a Ryane Clowe rebound and lifting it under the crossbar, and Irwin's point blast at the tail end of a power play made it 3-1 for the hosts with 3:29 remaining.
"That was a tough one to take," Couture said. "With a 3-1 lead going into the third, obviously you don't want to give it up. It's tough right now to get over, but we have a game tomorrow that we have to focus on. You think about the mistakes you made, move on, and get better from it."
Sobotka pulled the visitors within one at 4:18 of the third on a short-side shot from the right wing, then deflected in a Chris Stewart shot on the man advantage to forge a 3-3 deadlock 80 seconds later.
"It felt great," Sobotka said of the hat trick. "I don't know how to describe the feeling right now, but I feel great."
St. Louis has won five of the last six meetings with San Jose and avenged a 2-1 loss on Feb. 19 in the Gateway City ... Sobotka's trifecta also marked his first career multi-goal effort ... San Jose captain Joe Thornton celebrated his 1,100th NHL game ... Prior to the game, the Sharks made several roster moves, recalling Stalock and forward Matt Pelech from Worcester of the AHL, assigning goaltender Thomas Heemskerk to Worcester, activating forward Tommy Wingels off injured reserve and placing forward Martin Havlat on injured reserve.