The St. Louis Cardinals have a chance to leave Milwaukee with a commanding lead in the NL Central and could push the Brewers out of a playoff position.
Whether that happens might hinge on Adam Wainwright's performance.
Inconsistent since a victory in Milwaukee two months ago, Wainwright looks to become the fourth major leaguer to 17 wins in Sunday's finale to the four-game series.
St. Louis (78-64) arrived in Milwaukee with a three-game edge in the division and pushed that to four with a 5-3 victory Saturday. Kolten Wong hit a tiebreaking double in the fourth inning and Oscar Taveras followed with a two-run homer, allowing their team to overcome three errors.
The Cardinals, winners of seven of eight, also lead Pittsburgh by 4 1/2 games.
Wainwright (16-9, 2.69 ERA) is a win shy of tying Clayton Kershaw, Madison Bumgarner and Johnny Cueto for the major league lead despite going 4-5 with a 4.82 ERA in nine starts since the All-Star break.
The right-hander needed ample support, some from his own bat, to come away with a 6-4 win over the Pirates on Tuesday. He was charged with four runs in six-plus innings, all coming via a season-high three homers, but tried to make up for it with a career high-tying three RBIs.
"You can look at the three balls in the middle of the plate that got out, but I think most of the time I was much better tonight than I had been," he told MLB's official website. "That's what I am going to take from this start going forward. It was a much more quality game today than it has been. It's a similar line, but much better stuff, much different stuff."
Wainwright has a 3.00 ERA in his wins in the second half and a 6.52 mark in his defeats, including a 7-4 home loss to Milwaukee on Aug. 1. He matched a season high with seven runs allowed in 5 1-3 innings.
Wainwright was much sharper at Miller Park on July 12, yielding two runs in seven innings in a 10-2 victory. That performance capped a first half in which he went 12-4 with an MLB-leading 1.83 ERA in 19 starts.
He has a 4.74 ERA in losing his last three road starts after going 9-3 with a 1.32 ERA in his first 13 this year.
Wainwright likely won't face Carlos Gomez, who is still recovering from a sprained left wrist, and Ryan Braun is playing with nagging pain in his right hand. Braun went 1 for 4 with an RBI single in his team's 13th loss in 16 games.
The Brewers (74-68) have dropped into a tie with Atlanta for the NL's second wild card and are just one-half game up on Pittsburgh.
"At this point, my only focus is dealing with it the best we can, managing it," Braun said. "The trainers have been great. We're trying to stay on the field and compete the best I can."
If he plays Sunday, Braun will try to assist Jimmy Nelson (2-6, 4.14) in his attempt to snap a career-worst four consecutive losses. Nelson has received a combined seven runs of support in his last five starts.
The righty got two runs to work with Monday against the Chicago Cubs but gave up three along with a career high-tying nine hits over six innings in a 4-2 loss.
Nelson was charged with a career-worst eight runs - six earned - in 4 1-3 innings in his only start against St. Louis, the loss to Wainwright on July 12.