The Sharks lead the best-of-7 series 2-1 with Game 4 here on Friday (8 p.m. ET; NBCSN, CBC, TVAS).
Resiliency will be critical for the Blues after the way the Sharks rallied in Game 3.
"We did in the last series," captain Alex Pietrangelo said. "We were down against Dallas and came back [winning the second-round series in seven games]. We were down 2-0 tonight and came back.
"Again, we know how to look in the mirror and we know how to get better. We felt we had control of a lot of the game, so we'll use that recipe for next game. We've got depth. We just keep on playing and we play everybody. We just keep on pushing."
The Sharks opened a 2-0 lead in the first period in Game 3 on goals by Karlsson and Joe Thornton but trailed 4-3 after two periods when the Blues came to life with four second-period goals.
They held the lead until the final minute of the third period when the Sharks had pulled goalie Martin Jones for an extra attacker.
"We're a tough group in here," forward Alex Steen said. "I thought we came out good in the first 10 minutes and then kind of let our game slip a little bit but regrouped here in the room and came out and had a solid second. We'll do the same here in between games. We'll look back at this one and clean some things up. I think our execution, especially neutral zone stuff, will be a little bit crisper. We'll move forward and go onto Game 4 here."