With the single, Hart capped a wild finish to a game that had featured just one run through six innings. Over the final seven frames, the Cubs and Brewers combined to plate 14.
Hart also had a two-run game-tying homer in the ninth to extend the game. With a double in the fourth -- his first hit of the homestand -- Hart also snapped an 0-for-12 skid.
"He looked good, a lot of good at-bats," Roenicke said. "He looked good swinging the bat, as a lot of guys did today. We did a great job of coming back when we got behind."
Vinnie Chulk, the seventh pitcher out of the Brewers' bullpen and one of 16 used in the game between the teams, pitched a pair of scoreless innings to pick up the win.
Chulk started getting himself ready in the eighth and stayed that way until called upon in the 12th. Eventually, it was just Chulk left in the 'pen with bullpen catcher Marcus Hanel and bullpen coach Stan Kyles.
"I said, 'They're going to me. It's either me or you, Stan,'" Chulk said. "And they put me in."
Thanks to a pinch-hit grand slam by the Cubs' David DeJesus, the Brewers found themselves down, 4-1, in the seventh. With the bases loaded and Kameron Loe coming on to pitch, Cubs manager Dale Sveum called on DeJesus, who connected for his second career grand slam and first career pinch-hit home run.
DeJesus also had a triple in the ninth off Brewers closer John Axford, delivering the game-tying run for the Cubs.
"For not playing, whatever it was, seven innings, it was one heck of a game," Sveum said of DeJesus' performance.
Loe had been one of the Brewers' best pitchers, entering Friday's game with a club-best 1.93 ERA. He also had held opponents scoreless over his last seven appearances, while limiting them to just three hits in 6 1/3 innings.
After the Cubs' big inning, two walks, a double and a single set up Jonathan Lucroy for a big two-out pinch-hit in the bottom of the seventh. On a 1-1 pitch from Michael Bowden, Lucroy slapped a bases-clearing double into the right-field corner to put Milwaukee back ahead, 5-4.
"He threw me a slider first pitch, then he threw me a fastball for a ball, and then he threw the same slider again," Lucroy said. "I just tried to hit it hard, and it worked out."
Lucroy extended his hit streak to eight games with the double. He has 13 hits and seven RBIs during that stretch.
Axford had converted 49 straight save chances, but gave up three runs (one earned) in the ninth as Chicago took a short-lived 7-5 lead. Axford left immediately following the game, accompanying his wife to the hospital for the birth of their second child.
"The luck I've had in the past didn't show up tonight," Axford said in a note left for the media. "All I can do is begin another streak and keep my head up."
Before the seventh, both teams' offenses struggled to take advantage of pitching that was just a bit off the mark.
In 11 innings, starters Matt Garza and Randy Wolf combined to walk eight while giving up seven hits. But neither offense could capitalize, as one Brewers run was all that was on the board after six frames.
In the end, the game was just the type of chess match that Roenicke said he enjoys squaring off against Sveum, though a bit longer than he likely had hoped. The Brewers and Cubs will have a quick turnaround with Saturday's 12:05 p.m. CT start, but the Crew will hope to use Friday's victory as a potential momentum builder.
"It was important to win it," Roenicke said.