Cory Stillman and Pavol Demitra scored 52 seconds apart late in the second period as the Blues eliminated the Sharks, 2-1, to advance to the Western Conference semifinals.
The six-game victory sent St. Louis into the second round for the third time in the last four years.
"Anything can happen in Game Seven," Blues left wing Keith Tkachuk said. "We didn't want to take that chance. We had them down. We wanted to stick the fork in them and we finally did it today. But I'll tell you, it was an unbelievable series that could have gone either way."
With last season's playoff loss to the Sharks still fresh in their minds, the last thing the Blues wanted was another seventh game.
A year ago, St. Louis routed the Sharks, 6-2, in Game Six at San Jose and appeared to have all the momentum heading back home. But the Sharks stunned the Presidents' Trophy winners, 3-1, in Game Seven to win the series as the eighth seed.
Instead of looking ahead to another seventh game, the Blues can take a few days off to get ready for their next opponent.
"It was intense," St. Louis coach Joel Quenneville said. "Every game was extremely competitive. The Sharks play hard and they play mean. I thought we responded well to that physical challenge."
"They beat us in six games and won four games before we did," said Sharks center Mike Ricci. "They are a great hockey team and they did what they had do. Obviously, our power play didn't do the job and our penalty-kill probably didn't do it."
"I think we had to get a big goal out of a big-name player some time in the series to be able to win it," San Jose coach Darryl Sutter said.
"I thought I was useless the whole series," Selanne added. "I couldn't feel the puck at all. I'm very disappointed I couldn't help the team as best I can."
But San Jose did not go quietly. Defenseman Brad Stuart gave the Sharks life by scoring with 7:29 left in the third period. With six minutes left, San Jose nearly tied it, but goaltender Roman Turek made a pad save on Ricci's slap shot from the right faceoff circle.
San Jose continued to press for the equalizer, but the Blues survived a frantic final minute. Defenseman Chris Pronger blocked Selanne's blast from in close with 36 seconds left before Turek stopped Stuart twice in the final seconds.
"A lot of pucks were coming at the net and there was a lot of traffic," Pronger said. "We had six goalies out there, everybody trying to get in front of pucks and block shots."
"It was unbelievable pressure and they didn't score," added Turek.
Content to protect their lead, the Blues had only three shots in the final period. Sharks rookie Evgeni Nabokov returned to the nets after missing Games Four and Five and made 28 saves.
Turek stopped 30 shots for St. Louis and earned redemption after being roundly criticized for last year's playoff loss to the Sharks.
"Last year was my first playoff in the NHL and this year, before the last four or five games of the season, I started feeling very comfortable," Turek said.
"Roman played unbelievable," Blues center Pierre Turgeon said. "He stood on his head and he's a big difference in the series."
With both teams looking to avoid a mistake that could lead to the first goal, San Jose defenseman Jeff Norton took a critical roughing penalty with 5:50 left in the second period.
The Sharks nearly scored a shorthanded goal as Nolan intercepted a clearing attempt by St. Louis defenseman Al MacInnis but was stopped by Turek on a wraparound. The rebound caromed into the slot to defenseman Scott Hannan, who could not get off a clean slot and Turek covered a loose puck in the crease.
"You're always going to look at a situation like where a great missed opportunity is going to come back to haunt you," Sutter said. "It happened in a quick period of time."
With 4:40 left in the period, the Blues finally got on the board as Jochen Hecht sent a backhander in front to a wide-open Stillman, who beat Nabokov with a one-timer high to the stick side for his second goal of the series.
Less than a minute later, the Sharks were guilty of a devastating defensive breakdown, allowing Demitra to skate in alone on Nabokov. After taking a feed in the slot from Tkachuk, Demitra deked to his forehand and snapped a low shot that caromed in off the post for his first playoff goal.
Turek lost his shutout bid when Ricci passed in front to Stuart, who snapped a one-timer past the sliding goalie.