Ryan O'Reilly scored two goals, including the game-winner in the third period, and the Blues tied the best-of-7 series by defeating the Boston Bruins 4-2 in Game 4 at Enterprise Center on Monday for their first victory at home in a Cup Final (1-7).
The Blues improved to 7-2 after a loss in the playoffs, the latest win coming after they lost 7-2 in Game 3 on Saturday.
[WATCH: Bruins vs. Blues Game 4 coverage | Complete Stanley Cup Final coverage]
"We knew what we had to do tonight to be a better team," St. Louis coach Craig Berube said. "First of all, our discipline was a lot better, and second of all, just, we were relentless, I thought, tonight. We didn't stop for 60 minutes."
O'Reilly scored at 10:38 of the third period on the rebound of defenseman Alex Pietrangelo's shot to give the Blues a 3-2 lead.
He put St. Louis ahead 1-0 on a wraparound 43 seconds into the game, ending an eight-game goal drought dating to Game 1 of the Western Conference Final against the San Jose Sharks on May 11.
Video: BOS@STL, Gm4: O'Reilly pots early wraparound goal
Vladimir Tarasenko scored, Brayden Schenn had a goal and an assist, and Pietrangelo had two assists for the Blues. Jordan Binnington made 21 saves after he allowed five goals on 19 shots in Game 3.
"Things don't really seem to faze us," Pietrangelo said. "Obviously, last game got out of hand and we weren't too proud of that, but we felt like last game we did actually start pretty well the first 5-10 minutes, so we just used the same thing. We used everybody."
Video: BOS@STL, Gm4: Tarasenko buries rebound from the slot
Charlie Coyle and Brandon Carlo scored for the Bruins, who had a five-game road winning streak end. Tuukka Rask made 34 saves.
"From the get-go they were winning loose pucks, winning their battles," Coyle said. "They came hungry, and we need to do a better job. … We didn't have it as much as they did tonight."
Game 5 is at Boston on Thursday.
The Blues were 2-for-2 on the penalty kill after going 0-for-4 in Game 3.
O'Reilly's game-winning goal came 1:56 after St. Louis killed a penalty on defenseman Jay Bouwmeester for high-sticking Coyle.
Video: Clutch Performance: O'Reilly nets two in Game 4 win
Pietrangelo saw the Bruins were slow on a line change, so after quickly looking up, he put a high shot on Rask from the right face-off circle that handcuffed the goalie. The rebound dropped into the slot, and O'Reilly knocked it in in one motion after gaining inside position on Boston defenseman Charlie McAvoy, who had just come onto the ice.
"With the way it developed, we knew we were going to have something to the net with [Pietrangelo] coming down there," O'Reilly said. "I'm just trying to do what I can to get to that backside, and it just was a great bounce. It happens sometimes, and then you just try to throw it on the net."
The Bruins had to play with five defensemen for the final 36:53 because captain Zdeno Chara left the game after getting hit in the face by a shot from Schenn at 3:07 of the second period. He was on the bench for the third period wearing a full, clear face shield, but he was advised by doctors that he could not play.
Bruins coach Bruce Cassidy said he wasn't sure if Chara will be able to play in Game 5.
"With [Chara] out, the onus comes on us as a staff," Cassidy said. "You have [Connor] Clifton, McAvoy, [Brandon] Carlo, these kids are young. Torey's [Krug] been around, [John] Moore, but they're not old, grizzled veterans. So we have to coach them up. That's our challenge going into Game 5. We have to do a better job as a staff."
Video: BOS@STL, Gm4: Cassidy on Game 4 loss, Chara update
Coyle extended his goal streak to three games at 13:14 of the first, tying the game 1-1.
Tarasenko scored 2:16 later to give the Blues a 2-1 lead at 15:30.
Boston tied it 2-2 on Carlo's shorthanded goal at 14:19 of the second period. He is the 20th Bruins player with a goal in the 2019 playoffs.
Schenn scored an empty-net goal with 1:29 remaining for the 4-2 final.
Video: BOS@STL, Gm4: Carlo evens score while shorthanded
They said it
"Everyone in our lineup is confident, from the goalie up. Tuukka [Rask] has been great for us. He's been unbelievable for us. We've all got a little more in us, and we're going to need a little more." -- Bruins center Charlie Coyle
"The city has been waiting a long time for this. … It's a great sports city, an underrated sports city, in my opinion. The fans are great. They never gave up on us all season. They didn't give up on us here in the playoffs. We've been down, and they just keep on cheering, keep on supporting us. We're putting on the best effort we can for them." -- Blues captain Alex Pietrangelo
Need to know
This is the 16th time in the past 19 seasons years and 41st time in NHL history that the Cup Final will require at least six games. … O'Reilly had one goal in 17 playoff games since April 20. … Coyle is the third player in Bruins history to have a goal streak of at least three games in the Cup Final. Johnny Bucyk scored in all four games against the Blues in 1970, and Roy Conacher scored in four straight in 1939 against the Toronto Maple Leafs. … Blues defenseman Vince Dunn had an assist and three shots on goal in 12:57 in his first game since May 15. He missed the past six games with a mouth injury.
Game 5 of Stanley Cup Final at TD Garden on Thursday (8 p.m. ET; NBC, CBC, SN, TVAS)