Vladimir Tarasenko and St. Louis were in trouble Saturday before a vicious hit by Chicago defenseman Brent Seabrook provided an opening for the Blues.
That little crack was all St. Louis needed to put another dent in the Blackhawks' bid for a second straight Stanley Cup title.
Seabrook's blow to the head of David Backes led to a 6-on-4 power play for host St. Louis that ended with Tarasenko's tying goal with 6.4 seconds left in regulation, and low-scoring defenseman Barret Jackman ended the game with a drive through traffic, giving the Blues their second straight 4-3 overtime victory over the Blackhawks and a 2-0 series lead.
"Those seeing-eye shots, I couldn't believe it went in," Blues coach Ken Hitchcock said.
St. Louis took the opener in triple-overtime and fought off a Chicago rally in a game that began less than 39 hours later. Game 3 is Monday night in Chicago.
Blackhawks goalie Corey Crawford tossed his equipment around in the locker room before meeting with reporters. He said he was screened a bit on the game-winner, adding, "I had my pads together, but there was a little space there and it just kind of squeezed through."
Addressing the tying goal, Crawford said: "It's frustrating, but whatever. I'm not going to cry about it. We've just got to work harder."
Avalanche 4, Wild 2: Gabriel Landeskog scored twice and Semyon Varlamov stopped 30 shots, lifting host Colorado to a victory over Minnesota and a 2-0 series lead.
The Wild was unable to contain the quickness of teenager Nathan MacKinnon, who had a goal and three assists. Stastny, the star of Game 1, also had a goal and three assists. His empty-netter sealed the win after Marco Scandella made it a one-goal game with 1:19 remaining. Charlie Coyle also scored early for the Wild. Game 3 is Monday in Minnesota.
Blue Jackets 4, Penguins 3: Matt Calvert banged home a rebound 1:10 into the second overtime and Columbus earned the first playoff victory in franchise history with a win against host Pittsburgh.Pittsburgh's Marc-Andre Fleury stuffed the initial shot by Cam Atkinson but Calvert stood all alone at the left post and wristed a shot into the open net to even the Eastern Conference quarterfinals at one game each.
Game 3 is Monday in Columbus.
Jack Johnson tied the game with 6:01 left in regulation for the Blue Jackets. Sergei Bobrovsky overcame a shaky start to finish with 39 saves.
Flyers: Steve Mason (upper body injury) still isn't feeling well enough to play, so Ray Emery will be back in the net for Philadelphia in Game 2 against the New York Rangers on Sunday.
Bruins: Forward Milan Lucic has been fined $5,000 for spearing Detroit defenseman Danny DeKeyser during their opening playoff game.