Chicago's win and Milwaukee's loss assured the Cubs of their first National League Central Division Championship since 2003.
The Cubs' victory also snapped the team's three-game losing streak after Chicago was swept earlier in the week by last-place Florida at Dolphin Stadium in Miami.
Despite the three straight losses entering the night, Cubs manager Lou Piniella said his players "showed some emotion" in the clubhouse before the game.
Were they ticked off?
"No, it wasn't ticked off," Piniella said of the mood in the clubhouse. "It wasn't relief, but a sense of accomplishment of sorts. It was good to see. I like players in a team that will show some emotion at times, and they did tonight."
Piniella and the Cubs have shown emotion all year, from throwing punches at opposing players to throwing punches at one another.
Along the way, they fought back from 8.5 games behind in the Central Division to lead by as many as 3.5 games entering play Monday. The Cubs' 62-45 record since June 3 is the third best in all of baseball behind the Yankees and Colorado.
On Friday, two of the wealthiest players in all of baseball made sure that the recent late-season sweep didn't help lead to an all-out collapse.
Carlos Zambrano was in control from start to finish, tossing seven shutout innings and holding the Reds to six hits and a walk. Zambrano (18-13) struck out four while notching his career-high 18th regular season victory.
"He did a nice job and his sinker was really moving," Piniella said after the game.
Zambrano, who received a five-year, $91.5 million contract extension with an option for 2013 earlier this season, hasn't allowed a run in his last two starts.
In September, the right-hander is 4-2 with a 3.44 ERA in six starts.
In the first inning, $136 million man Alfonso Soriano led off the game with a home run to right-center – his 32nd this season; 13th this month – on a 0-2 fastball. He finished with two hits, including his 41st double.
Soriano also contributed his 19th outfield assist, gunning down Cincinnati's Joey Votto on a throw to the plate in the fourth inning to preserve a 2-0 lead.
"He made an outstanding throw," Piniella said.
With good defense behind them all night, the Cubs added two more runs a half-inning later on Derrek Lee's two-run homer. That made it 4-0, and the Cubs got two more in the eighth when Jacque Jones hit a two-run double to make it 6-0.
Ryan Dempster pitched a scoreless ninth inning in a non-save situation, recording the final outs when former Cubs prospect Buck Coats hit into a game-ending 6-4-3 double play to reduce Chicago's then-Magic Number to 1 game.
"This is the type of game that we need to play," Piniella said afterward. "We need to get good starting pitching and we need to take leads, and then we can turn the game over to our bullpen. It's really been our formula for most of our success."
The game may have been played in Cincinnati, but the crowd – much like the game itself – was in the division champions' favor.
The announced crowd of 32,193 were mostly clad in Cubs gear, and scoreboard updates of the Padres taking the lead at Miller Park were met with just as much enthusiasm from the pro-Cubs crowd as Zambrano's clutch pitches and Soriano's extra-base hits.
Piniella said after the game that he hoped for "one more" – meaning a Cubs win or a Milwaukee loss. That came just over an hour later when Trevor Hoffman struck out the side in the ninth inning to send the Brewers to their third consecutive defeat.
Information from the Cubs' Media Relations Office was used in this report.