"It's 162 games," Cubs starter John Lackey said. "You're going to end up being who you are. The best team comes out in the wash after 162 games. We're the best team in this division."
The Cubs players ran onto the field after Wade Davis induced Randal Grichuk to fly out to Leonys Martin in center field for the final out and crowded onto the mound to begin the celebration. Reliever Carl Edwards Jr. was waving a "W" flag.
"To be able to do it here in St. Louis, the series that was anticipated when we would do it, was definitely cool," Cubs shortstop Addison Russell said. "These guys have been great all year. We started out a little bit slow, but I knew as the year went out, we'd get better and better. We started out with a goal in Spring Training and we've hit that goal every single day. I feel we're playing our best baseball right now."
"Any time you beat somebody in your division, it's always good, regardless if it's [the Cardinals], the Brewers, the Pirates, the Reds," Chicago pitcher Jon Lester said. "If you beat somebody in your division and have a good record against your division, you'll find you're in a pretty good position."
All the while, the Cubs also put the Cardinals' playoff hopes on life support. With their elimination number reduced to one, the Cardinals are in jeopardy of falling out of postseason contention on Thursday with another loss. St. Louis trails Colorado by 3 1/2 games for that second NL Wild Card spot.
It took an offensive eruption in the seventh for the Cubs to become the first defending World Series champs to win their division the following year since the 2009 Phillies. Held to two singles over Wacha's first six innings, the Cubs pounced on the Cardinals' starter the third time through the order. The first seven batters reached, and Russell delivered the big blow with a three-run homer that stayed just feet inside the left-field foul line.
Jason Heyward and pinch-hitter Tommy La Stella tacked on RBI doubles as insurance. All five runs were charged to Wacha, who finishes the regular season with a 4.13 ERA.
"It happened in a hurry, and it was unfortunate because he had special stuff today," Matheny said. "The little extra life on the fastball was missing there in the seventh all of a sudden."
Before things unraveled, Wacha breezed through six innings on 60 pitches. The Cubs stayed close, though, because Lackey nearly matched him. Lackey spotted the Cardinals a lead by allowing a second-inning run before holding them hitless the rest of the way through his six-inning start.
The Cubs won all four games Lackey started against the Cardinals this year and hold a 13-5 advantage in the season series.
"The boys stepped up," Lackey said of his teammates. "We had some tough series the last few weeks. It could've broke us down the stretch and we played pretty dang good."
The Cardinals must win out to have any chance at returning to the postseason.
"I know we're not in a very good situation, but it's all about just coming out and maybe some stuff will happen where we have a chance," Wacha said. "We just have to take care of our own business and keep winning."
MOMENTS THAT MATTERED Russell's game-changing swing: The Cubs generated their first bit of offensive momentum by opening the seventh with two singles that scooted past first baseman Jose Martinez. That brought the inning to Russell, who, after working into a favorable count, crushed a 92-mph cutter from Wacha. Off the bat, the only question was whether the ball would stay fair. It did, giving the Cubs their first lead since Monday and Russell his 12th homer of the season. He has two three-RBI games in this series.
One last gasp: Maddon had to run through three relievers to navigate the eighth, which represented the Cardinals' best chance to flip things late. After Greg Garcia beat out a potential inning-ending double play, the Cards loaded the bases with a Luke Voit single and walk to Tommy Pham. Former Cub Dexter Fowler, 1-for-5 in his career against Edwards, had a chance to tie the game with one swing, but instead flied out to close the inning.
QUOTABLE "Baseball is designed to pick you off in a given year when things don't go your way. We've had years when everything broke our way like last year, and we've had years when we've had to overcome things like this year. To be in [the postseason] three years in a row, that's how you win championships, and if we keep this going, that's how you win multiple championships. That's what we're here for." -- Cubs president of baseball operations Theo Epstein
WHAT'S NEXT Cubs:Kyle Hendricks will make his 24th start of the season Thursday in the series finale. Hendricks is coming off a strong outing against the Brewers in which he gave up one run over six innings. He's 6-4 with a 2.73 ERA in his last 20 starts. First pitch is scheduled for 6:15 p.m. CT at Busch Stadium.
Cardinals: In what is likely to be his final start as a Cardinal, Lance Lynn will start Thursday against the Cubs. Lynn will look to finish his time in St. Louis on a high note and also to bounce back from the roughest start of his career. He allowed eight runs without finishing the first inning.