Anthony Rizzo turned on the power with a long homer down the right-field line in the 11th inning. Jason Heyward delivered a tying single in the eighth against one of the toughest relievers in baseball.
The Chicago Cubs dented the Milwaukee Brewers' normally lights-out bullpen to return to first place in the NL Central.
Rizzo's shot opened the scoring in a five-run 11th, and Heyward drove in three runs during a 7-2 victory that gave the Cubs a half-game lead in the division.
"Today we piled on late. You could see what we're capable of doing," manager Joe Maddon said.
Rizzo hit a fastball down the middle from Matt Albers (3-2) for a towering shot that snapped a 2-all tie. The Cubs scored four more runs in the inning with two outs, including a two-run double by Heyward.
Trailing 2-1 most of the night, the Cubs scored six times over the last four innings against the Brewers' formidable bullpen. They won their seventh straight over Milwaukee.
"It would be nice to get (the offense) rolling, whether it's earlier in the game with runners in scoring position ... take some heat off the bullpen and not have to play extra innings," Maddon said.
Cubs relievers tossed five scoreless innings, with Randy Rosario (3-0) retiring all six batters he faced for the win.
"They do all the little things well. They don't make mistakes," Brewers outfielder Ryan Braun said. "We still have to get better at some of those things I think to consistently play as good of baseball as they do."
After being held to one run by Brewers starter Junior Guerra, the Cubs broke through in the eighth against a bullpen with a league-best 2.53 ERA. The left-handed-hitting Heyward, who had three hits, tied the game at 2 with a run-scoring single to right off lefty reliever Josh Hader.
Left-handed hitters were 2 for 36 against Hader before Heyward's single.
"We just know the guy's got good stuff," Heyward said. "So if something's there, just keep it simple, take what he gives you."
ON THE MOUND
Albers allowed five runs and three hits, leaving with two outs in the 11th. His ERA ballooned from 1.93 to 3.45.
He said he was expecting Rizzo to swing at the first pitch. But his fastball didn't sail up and in as planned.
"I just didn't quite get it to the spot I wanted to. That's pretty much the story of my outing there — just not executing," Albers said.
Guerra struck out four while allowing five hits and two walks, aided by two double plays and two highlight-reel catches in left by Braun.
He made a diving grab to prevent Rizzo's flare from falling for a hit to lead off the fourth. Two innings later, Braun made a leaping catch at the wall to rob Willson Contreras of a tying homer.
Braun held the glove behind his back after coming down with the ball and swaggered for a few steps toward the infield before shrugging and revealing the ball in his mitt.
"It was a lot more fun than when they scored all those runs, but I take a lot of pride in my defense," Braun said.
ON THE MOUND
The Cubs got an effective outing from starter Jose Quintana, who allowed four hits, two walks and struck out three over six innings. The left-hander gave up solo homers to Erik Kratz and Jonathan Villar.
Cubs: Maddon said RHP Yu Darvish (right triceps tendinitis) is scheduled to throw a bullpen in Milwaukee on Tuesday, as long as there wasn't "any kind of negativity" while Darvish played catch Monday.
Brewers: Eric Thames was reinstated from the 10-day disabled list after missing six weeks with a torn ligament in his left thumb. While eager to get an at-bat, Thames did not play. "My hands, I've been doing so much grip stuff I can crush anything," he said before the game.
Cubs: RHP Tyler Chatwood (3-4) hopes to have better control after walking seven in his last outing against the Phillies.
Brewers: RHP Chase Anderson (4-5) has a 2.79 ERA over his last three starts against Chicago. But the Brewers have been shut out each time, outscored by a combined 9-0.