Kyle Schwarber went deep to left-center field in the second inning, and Kris Bryant crushed a two-run shot to left in the fifth. Bryant's homer was the Cubs' second of six in the game and the 10th hit by a rookie overall in the postseason, setting a new Major League record.
"Any time the wind is blowing out here, you've really got to take advantage of it," Bryant said. "Get some pitches that you can hit in the air, and you never know what can happen."
By the end of the night, the rookie record Bryant set would climb to 12. Continuing his incredible start to the postseason, Cubs outfielder Jorge Soler added a two-run shot in the sixth inning.
With one on and one out, Soler launched the first pitch he saw from Adam Wainwright into the left-center-field seats to put the Cubs ahead, 7-4. Soler's two-run blast was his second in as many games, as he homered in the Cubs' 6-3 win in Game 2 on Saturday at Busch Stadium. It also made Soler the first player to ever reach base in his first nine postseason plate appearances, according to the Elias Sports Bureau. The previous record was five.
Soler's streak also set a Cubs postseason record (not just to begin a career), surpassing the previous high mark of seven set by Hack Wilson in 1929.
"I've got tremendous confidence right now," Soler said through bench coach Dave Martinez, who translated. "I'm seeing the ball really well, and I'm just trying to get on base and help our team win."
Cardinals rookie Stephen Piscotty hit a two-run shot in the ninth to extend the total to 12. Rookie hitters went deep nine times over 28 postseason games in 2007 and eight times in 32 games last year. This year's dynamic rookie class shattered the record before the end of a single Division Series.
Led by their trio of rookie sluggers, the Cubs made a little history of their own Monday night.
Dexter Fowler went deep in the eighth to give the Cubs an 8-4 lead as Chicago set a record for a postseason game with six home runs. The eight home runs combined by the two teams -- Jason Heyward also homered for St. Louis -- set a record for a postseason game.
Starlin Castro and Anthony Rizzo also homered, making the Cubs the first team in Major League history to have five different players under the age of 27 hit a homer in a postseason game. Only two teams, the 2013 Astros and 1996 Brewers, have even done that in a regular-season game.
The Cubs also set a single-game postseason record with six homers from six different players.
The White Sox were the last team to hit five homers in a postseason game, doing so against the Red Sox in the 2005 American League Division Series. The Cubs were already one of only five teams to go deep five times in one postseason game. They hit five on Oct. 2, 1984, against the Padres in Game 1 of the NL Championship Series.
Schwarber's shot to left-center field was his second home run of the postseason, as he also went deep in the Cubs' NL Wild Card Game win over the Pirates on Wednesday night at PNC Park.
Schwarber, Soler, Piscotty and Astros shortstop Carlos Correa have each homered twice in the postseason. Bryant and two Cardinals -- Randal Grichuk and Tommy Pham -- have each hit one. Rounding out the group of home run-hitting rookies is Mets outfielder Michael Conforto.
Soler, Schwarber and Bryant are the youngest set of three teammates ever to hit a home run in the same postseason. Schwarber and Soler are the first Cubs rookies to hit two postseason homers.
All that history, all those records -- gone with the wind.
"It's just like any other Wrigley day," Schwarber said. "You don't know if it's going to blow in or blow out. It just happened to be blowing out today."
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.