CHICAGO -- Chicago Blackhawks right winger Dale Weise knew to skate to the left circle and release a high, hard shot as quickly as possible.

At long last, the puck found the back of the net.

Weise picked a perfect moment to snap an 18-game scoring drought and notch his first goal as a member of the Blackhawks. He scored the go-ahead goal late in the second period, and Chicago staved off elimination with a 6-3 comeback win over the St. Louis Blues on Saturday night.

The Blackhawks scored the final five goals of the game to even the series at 3-3 in the best-of-seven Western Conference quarterfinal matchup. Game 7 is scheduled for Monday in St. Louis.

"We do a drill in the morning where it's kind of the same play," Weise said. "I've felt good in practice, but haven't been able to do it in games lately. That one feels good to get the monkey off my back."

As for the Blues, the postseason monkey is hanging on tight.

St. Louis squandered a 3-1 lead as Chicago tallied three goals in the second period and two more in the third period. The Blues also let a 3-1 series lead slip away and must win Game 7 to avoid their fourth consecutive first-round exit in the playoffs.

"They had a big surge, and we didn't answer," St. Louis coach Ken Hitchcock said. "Their surges have been in the second period, and we didn't answer it as well as we should have. They played at a pace that we struggled with until we regrouped in the third and came back at them."

Andrew Ladd, Trevor van Riemsdyk and Weise produced even-strength goals for the Blackhawks. Artem Anisimov and Andrew Shaw scored on the power play, and Marian Hossa added an empty-net goal.

Chicago improved to 13-4 in elimination games under coach Joel Quenneville.

"I think that when we were down 3-1 (in the series), we had nothing to lose and the pressure was on them," Quenneville said. "Now, it's even more so. It's one game. I know that we've got momentum."

Never was that momentum on display more than the second period Saturday. Anisimov, van Riemsdyk and Weise scored in a 12:05 span to transform a two-goal deficit into a one-goal lead.

"That snowball effect of momentum just keeps building and building," said Shaw, who provided a consistent net-front presence as he returned from a one-game suspension. "It created confidence through all four lines and we had some big goals."

Chicago goaltender Corey Crawford stopped 25 of 28 shots for the victory.

St. Louis goaltender Brian Elliott turned aside 30 of 35 shots.

In the visitors' locker room, the Blues vowed to learn from their mistakes. Chicago outshot St. Louis 19-6 during the second period and finished the game with a 36-28 advantage in shots on goal.

"I think our second period was a little bit hesitant," Blues left winger Alexander Steen said. "They come out and give us a good push, and we almost squeezed the sticks a little bit and started playing a little too hesitant, too defensive, giving them a little too much gap.

"We've got to stay on top of them and keep playing, keep pressing forward the way we have. That's the reason why we came out of the first period with a 3-1 lead."

St. Louis took a 3-1 lead thanks to goals by Scottie Upshall, Alex Pietrangelo and Vladimir Tarasenko.

A power-play goal by Anisimov cut Chicago's deficit to 3-2 with 15:47 to go in the second period.

Chicago evened the score at 3 on van Riemsdyk's first goal with 7:39 remaining in the second period.

Weise gave Chicago a 4-3 lead on a one-timer with 3:42 remaining in the second period.

Shaw and Hossa increased the lead with third-period goals.

Chicago will face St. Louis in a deciding Game 7 for the first time since 1990.

"Let's go in there, have some fun," Quenneville said.

NOTES: Blackhawks LW Andrew Shaw returned from a one-game suspension for using a homophobic slur during Game 4 of the best-of-seven Western Conference quarterfinal series. Shaw skated on Chicago's top line alongside C Jonathan Toews and RW Patrick Kane. ... Blues D Joel Edmundson was a healthy scratch for the second consecutive game and D Carl Gunnarsson remained in the lineup. ... Blackhawks LW Tomas Fleischmann was a healthy scratch for the second straight game. Fleischmann, 31, had 14 goals and 11 assists in 76 games with Montreal and Chicago during the regular season. ... Blues RW Steve Ott played his fourth straight game after missing the previous four months because of injuries. RW Ryan Reaves was a healthy scratch. ... Blackhawks RW Marian Hossa appeared in his 200th career playoff game.