CHICAGO -- The Chicago Cubs used a major league postseason record six home runs to seize command of their National League Division Series on Monday.

But they are taking nothing for granted even with a chance to close out the series following an 8-6 victory over the St. Louis Cardinals.

"It's difficult to finish off good teams," said Cubs manager Joe Maddon. "We've been behind a lot of times, we've battled back. We totally expect that out of the Cardinals. ... You don't pack up the bats until the last out ever."

Chicago won its second straight to take a 2-1 lead in the best-of-five series. The Cubs, who beat the Pittsburgh Pirates in the NL wild-card game last week, would clinch a berth in the NL Championship Series with a Tuesday victory at Wrigley Field.

Six different Cubs homered on Monday to also break a team record of five set against the San Diego Padres in the 1984 NL Championship series.

Rookie third baseman Kris Bryant had a key blast -- a two-run homer in a three-run fifth that gave the Cubs a 4-2 lead. First baseman Anthony Rizzo followed with a solo shot to make it 5-2 in front of an announced crowd of 42,411.

"I'm not doing anything different at all," said Bryant, who broke out of an 0-for-11 skid with his 2-for-5 night. "I saw the ball really good. It's a monkey off my back and we move on from there."

Left fielder Kyle Schwarber, second baseman Starlin Castro, right fielder Jorge Soler and center fielder Dexter Fowler also went deep for Chicago.

The Cardinals played catchup from the second inning on.

"We were fighting from a deficit there right from the start," said Cardinals manager Mike Matheny. "We had an opportunity early to make something happen, couldn't get the run over and in and that's the kind of thing you like to see happen to set the tone."

Cubs right-hander Jake Arrieta improved to 2-0 in the postseason despite allowing four runs in 5 2/3 innings.

"(Jake) wasn't as sharp as he normally is," Maddon said. "I was plotting, planning mentally when is this going to come to an end tonight. ... Of course, he still had good stuff, he just wasn't as sharp as he normally is."

Cardinals right-hander Michael Wacha took the loss after giving up four runs in 4 1/3 innings.

"They jumped on Michael for a couple and I thought he got better as he went and really did manage damage overall," Matheny said.

St. Louis trimmed a 5-2 deficit to a single run in the sixth with right fielder Jason Heyward's two-run home run to left off Arrieta that scored left fielder Matt Holliday.

Arrieta departed after hitting pinch hitter Brandon Moss with a pitch. It was the Chicago ace's shortest outing since he allowed four runs in five innings in a May 16 loss to the Cleveland Indians.

On Monday, Arrieta gave up five hits while walking two and striking out nine.

Soler got the runs right back in the bottom of the sixth. His first-pitch homer to left scored pinch hitter Chris Coghlan and gave the Cubs a 7-4 lead.

Fowler added a one-out solo shot in the eighth off right-hander Jonathan Broxton.

Cardinals first baseman Stephen Piscotty's two-run, ninth-inning homer with two outs cut the Cubs' lead to 8-6.

Schwarber's one-out solo homer in the second inning opened a 1-0 Cubs lead. Schwarber, who sat out Game 2 in St. Louis, sent Wacha's 2-2 pitch into the left-field bleachers for his second homer of the postseason and 18th overall.

The Cardinals jumped in front 2-1 in the fourth. Arrieta opened the inning with walks to Piscotty and Holliday. Shortstop Jhonny Peralta doubled home Piscotty, and center fielder Tommy Pham brought in Holliday on a fielder's choice to third.

In the bottom of the fourth, Castro tied the game 2-2 with a first-pitch solo homer that went 413 feet to the left-field bleachers.

Later in the inning, shortstop Addison Russell tripled to deep left with two outs but departed the game with a left hamstring strain. Javier Baez, who entered as a pinch runner for Russell, remained in the game at shortstop.

Bryant made it 4-2 in the fifth, connecting on Wacha's 3-2 pitch for a two-run homer to left. The homer -- his first of the postseason -- brought home Soler and earned a curtain call from Cubs fans.

That was it for Wacha, pulled for left-hander Kevin Siegrist. Wacha, who allowed three homers, walked three and struck out five.

Rizzo greeted Siegrist with a solo home run to right, his first of the playoffs, for a 5-2 Chicago lead.

NOTES: The Cardinals entered Monday's NLDS game with an 11-8 regular-season edge over the Cubs but only four wins in nine games at Wrigley Field. The series is the first-ever postseason meeting between the teams. ... St. Louis C Yadier Molina is appearing in his ninth postseason (2004-06, 2009, 2011-15) and is the Cardinals' all-time postseason leader in hits, games played and at-bats. ... Cardinals manager Mike Matheny said RHP John Lackey (13-10, 2.77 ERA) will start on Tuesday in place of RHP Lance Lynn, who was originally tabbed. ... The Cubs will send RHP Jason Hammel (10-7, 3.74 ERA) to the mound for Game 4.