Bo Horvat scored twice and the Vancouver Canucks beat the defending Stanley Cup champion St. Louis Blues 5-2 on Wednesday in the opening game of their best-of-seven first-round series.

J.T. Miller, Elias Pettersson and Troy Stecher also scored for Vancouver.

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Vancouver Canucks' Quinn Hughes (43) and St. Louis Blues' Zach Sanford (12) battle for the puck during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Bo Horvat scored twice and the Vancouver Canucks beat the defending Stanley Cup champion St. Louis Blues 5-2 on Wednesday in the opening game of their best-of-seven first-round series.

Vancouver Canucks' Tyler Myers (57) chases St. Louis Blues' Vladimir Tarasenko (91) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Game 2 is set for Friday night.

Vancouver Canucks goalie Jacob Markstrom (25) stops St. Louis Blues' Tyler Bozak (21) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

The Canucks were making their first playoff appearance since 2015, having defeated the Minnesota Wild in the qualifying round.

St. Louis Blues goalie Jordan Binnington reacts after giving up a goal to the Vancouver Canucks during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Horvat opened the scoring about five minutes in when he one-timed a feed from Hughes from the top of the left circle past St. Louis goalie Jordan Binnington.

Vancouver Canucks' Bo Horvat (53), Troy Stecher (51) and Brock Boeser (6) celebrate a goal against the St. Louis Blues during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

The Blues tied it just over a minute later when Schwartz tipped the puck past pinching Canuck defenseman Chris Tanev at the Blues' blue line, then charged in on a breakaway and beat Markstrom with a nifty backhander through the pads.

David Perron and Jaden Schwartz scored for St. Louis.

Vancouver Canucks' Quinn Hughes (43) and St. Louis Blues' Zach Sanford (12) battle for the puck during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Vancouver Canucks' Quinn Hughes (43) and St. Louis Blues' Zach Sanford (12) battle for the puck during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Game 2 is set for Friday night.

Horvat has four goals in return-to-play action while rookie teammate Quinn Hughes logged an assist to reach seven points (one goal, six helpers) in five games.

Jacob Markstrom made 29 stops for the win.

Vancouver Canucks' Tyler Myers (57) chases St. Louis Blues' Vladimir Tarasenko (91) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Vancouver Canucks' Tyler Myers (57) chases St. Louis Blues' Vladimir Tarasenko (91) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

The Canucks were making their first playoff appearance since 2015, having defeated the Minnesota Wild in the qualifying round.

They never trailed in the game.

The teams swapped mirror-image power-play goals in the first period.

Vancouver Canucks goalie Jacob Markstrom (25) stops St. Louis Blues' Tyler Bozak (21) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Vancouver Canucks goalie Jacob Markstrom (25) stops St. Louis Blues' Tyler Bozak (21) during the second period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Horvat opened the scoring about five minutes in when he one-timed a feed from Hughes from the top of the left circle past St. Louis goalie Jordan Binnington.

St. Louis countered with under four minutes to go. Perron slapped a pass from Brayden Schenn from the top of the right circle high over the glove of Markstrom.

Vancouver regained the lead on the power play midway through the second period. Pettersson whipped the puck under the bar off a goalmouth scramble for his second goal.

St. Louis Blues goalie Jordan Binnington reacts after giving up a goal to the Vancouver Canucks during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

St. Louis Blues goalie Jordan Binnington reacts after giving up a goal to the Vancouver Canucks during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

The Blues tied it just over a minute later when Schwartz tipped the puck past pinching Canuck defenseman Chris Tanev at the Blues' blue line, then charged in on a breakaway and beat Markstrom with a nifty backhander through the pads.

Vancouver took the lead for good almost six minutes into the third. Stecher raced down the right wing and wired a slap shot from the circle under Binnington’s arm for his first of the postseason.

Then Horvat turned Blues defenseman Vince Dunn inside out, raced in and fired a wrist shot past Binnington on the blocker side.

Vancouver Canucks' Bo Horvat (53), Troy Stecher (51) and Brock Boeser (6) celebrate a goal against the St. Louis Blues during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Vancouver Canucks' Bo Horvat (53), Troy Stecher (51) and Brock Boeser (6) celebrate a goal against the St. Louis Blues during the third period in Game 1 of an NHL hockey Stanley Cup first-round playoff series, Wednesday, Aug. 12, 2020, in Edmonton, Alberta. (Jason FransonThe Canadian Press via AP)

Miller added the fifth goal on the power play with less than 40 seconds left.

The Canucks are winning with a mix of veterans and playoff newbies.

Pettersson, Brock Boeser, Jake Virtanen, Tyler Motte, Hughes, Stecher, Zack MacEwen, and Markstrom were regulars playing in their first playoff game (although technically they have playoff experience as the qualifying round statistics will count as post-season ones).

NOTES: St. Louis was the best in the Western Conference (42-19-10) and second overall in the league when the NHL suspended play March 12 due to the COVID-19 pandemic. In the return to action, they have squandered third-period leads in every game and have scored just six goals in three contests. ... History is on Vancouver’s side. The teams have met three times in the playoffs (1995, 2003 and 2009). Each time the Canucks bounced the Blues out in the first round.

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Game 2 is set for Friday night.

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