A long slog of a rainy Monday night in St. Louis turned out to be a very productive one for the Milwaukee Brewers, thanks to some help from a National League Central rival.

Milwaukee's come-from-behind 6-4 win over the Cardinals, combined with Pittsburgh's 5-1 victory at the Chicago Cubs, inched the Brewers within 1 1/2 games of Chicago for first place in the division. It also assured them of leaving their showdown series at Busch Stadium with no worse than the NL's first wild card spot.

Milwaukee can win the series and continue to apply pressure on teams ahead of and behind it by taking the middle game of the three-game set Tuesday night.

The Brewers (90-67) prevailed by rolling the dice and taking advantage of St. Louis' generosity. Although scheduled starter Chase Anderson usually pitches well against the Cardinals, manager Craig Counsell scratched him in favor of a nine-inning bullpen game that emphasized using left-handers against MVP candidate Matt Carpenter.

The strategy worked, aside from Carpenter's RBI double in the third against rookie righty Freddy Peralta. St. Louis also pitched in six walks, a hit batter and a throwing error over the last four innings, enabling the Brewers to score five runs in that span.

Counsell said his team would approach the game as though it were another game, not trumping up its importance relative to the playoff push. While his insertion of All-Star reliever Josh Hader in the fifth inning belied that philosophy, Counsell's message wasn't lost on his team.

"We've got to focus on every night individually," said Milwaukee outfielder and possible MVP favorite Christian Yelich to mlb.com. "You can't get caught up in the long-term picture. You've just got to focus on every day and put all your energy into winning that night."

To capture the series, the Brewers will turn to August 31 trade acquisition Gio Gonzalez (9-11, 4.28), who will make his fourth start with the team. His last was his best, as he blanked Cincinnati over six innings Wednesday night in a 7-0 win, giving up two hits and two walks while whiffing five.

While Gonzalez allowed five hits and five runs in four innings of a 6-4 loss August 14 to the Cardinals in one of his last starts with Washington, he has usually pitched well against St. Louis. In nine career starts, he's 3-4 with a 2.97 earned run average and a shutout.

The Cardinals (87-70) will turn to rookie left-hander Austin Gomber (6-1, 3.63) in an effort to maintain their half-game advantage on Colorado for the second wild-card spot. Gomber posted an 8-1 win on Sept. 18 at Atlanta in his last outing, permitting a run on six hits and three walks over five innings. He fanned five.

It will be Gomber's first career start against Milwaukee and his second career appearance. He pitched two-thirds of an inning in a relief outing earlier this year, erasing a hit and a hit batter with a double play ball.

St. Louis manager Mike Shildt acknowledged Monday night's setback was frustrating, given that his team reached the normally unhittable Hader for three runs in the sixth inning to take a short-lived 4-3 edge.

"It's one of those deals where we didn't help ourselves," he said. "The walks ultimately hurt you. Any time you give something to the competition, it's going to hurt you."