Scott Young scored three times on Sunday and the Blues, trying to match last year's feat of rallying from a 3-1 deficit to win a first-round series, defeated the San Jose Sharks 6-2 to even their series at three games apiece.
Game 7 is on Tuesday night at St Louis.
Young, who has five goals in the series, opened the scoring in the first period and added two more goals as the Blues took a 6-0 lead midway through the second.
Jochen Hecht had a goal and three assists for St Louis, which had three goals on three shots in a 2:40 span of the second period and set a team record with the five goals in one period. Chris Pronger and Tyson Nash also scored for the Blues, and Pierre Turgeon had three assists.
The Blues, the best road team in the NHL during the regular season, scored six times on their first 13 shots. They took 24 shots overall, while the Sharks fired 27 at goalie Roman Turek.
Owen Nolan and Bryan Marchment scored for the Sharks, who have never won a series-clinching game on their home ice in San Jose. It was Nolan's fifth goal of the series, but his first since Game 3.
The Blues are following a script similar to last year's first-round ouster of Phoenix, but with an important difference.
Just as in the 1999 postseason, they lost Games 2, 3, and 4 and rallied to win Games 5 and 6. Last year, they had to win Game 7 at Phoenix. This time, the decisive game will be on their home ice.
St. Louis is trying to become the 16th team in NHL history to win after trailing 3-1 in a series. They also pulled off the feat in 1991, when they rallied to defeat Detroit in the first round. No team has done it in consecutive years.
The Blues opened the scoring when Turgeon fought off a defender while bringing the puck up the ice and passed to Hecht, who slid a pass to a wide-open Young at the side of the net with 7:29 left in the first period.
Young made it 2-0 just 21 seconds into the second when he got a rebound and flicked a 25-foot shot over Shields' right shoulder. Hecht completed a give-and-go with Turgeon to make it 3-0 while the teams both skated a man down midway through the period.
Then the roof caved in for Shields and the Sharks. Pronger's shot trickled out of Shields' glove and into the net with 8:18 left in the period, Nash scored 69 seconds later on a shot that went off Shields' stick hand and Young completed his hat trick with a power-play goal with 5:38 remaining in the period.
Nolan scored a power-play goal for San Jose with 2:47 left in the second period and Marchment scored with four minutes left in the game.