CHICAGO (Interstat) — In a frantic, back-and-forth opening inning that saw all seven of the game’s runs cross the plate, the Chicago Cubs outlasted the Milwaukee Brewers 4-3 on Wednesday at a raucous Wrigley Field to secure their first victory of the National League Division Series.

A crowd of 40,737 watched as the Cubs clawed back from an early deficit to cut Milwaukee’s series lead to 2-1 in the best-of-five matchup. Game 4 is scheduled for Thursday in Chicago.

The Brewers struck immediately against Cubs starter Jameson Taillon. Christian Yelich led off the game with a double and later scored on a sacrifice fly by Sal Frelick. The early run seemed to set the tone for the visitors, but the Cubs had a thunderous response waiting in the bottom half of the frame.

Facing Milwaukee starter Quinn Priester, Michael Busch launched a three-run home run to right-center field, instantly flipping the script and energizing the home crowd. The Cubs were not done. They loaded the bases before Pete Crow-Armstrong lined a two-run single to right field, capping a four-run inning that ultimately decided the game.

“An incredible first inning,“ said a Cubs team spokesperson. “The guys showed a lot of fight to answer back like that.“

Priester, who entered the game with a 13-4 record, was charged with the loss. He lasted just one inning, surrendering four runs on four hits and three walks.

From there, the game transformed into a bullpen duel. The Brewers’ relief corps of Jose Quintana, Grant Anderson, Chad Patrick and Nick Mears combined for seven scoreless innings, allowing just three hits and keeping their team within striking distance.

Milwaukee chipped away, scoring a run in the fourth on an RBI single by Jake Bauers that plated Frelick. Bauers then brought the Brewers to within a run in the seventh, launching a solo home run to left-center field off Cubs reliever Drew Pomeranz.

The Brewers threatened to tie or take the lead in the eighth, loading the bases with two outs. Jackson Chourio stood on third after a double, but Cubs closer Brad Keller entered the game and struck out Bauers on a foul tip to end the inning.

Keller then worked a perfect ninth inning, striking out Blake Perkins and getting Yelich to ground out to seal the victory and earn his fifth save of the season.

Pomeranz, who recorded two strikeouts in a scoreless inning of work, was credited with the win.

The Cubs’ bullpen, a combination of Pomeranz, Caleb Thielbar, Daniel Palencia and Keller, provided five shutout innings of relief after Taillon departed, allowing just two hits.

The victory improves the Cubs’ season record to 95-73, while the Brewers, who had won the first two games of the series at home, fell to 99-66.