"It put them back on the ropes," starter Manny Parra said. The momentum could have swung, but that put them right back in a hole."
Parra (3-4) won his third straight start and the Brewers got two-run singles from J.J. Hardy and Jason Kendall with two outs in the first to win their fifth in a row. They're 19-5 since a 4-9 start.
"Everything seems to be going together right now," Parra said. "It's just been a lot of fun, and it makes it a lot of fun to come to the ballpark when we're playing this way."
The Brewers are 12-5 against the Cardinals the last two seasons.
St. Louis, minus injured sluggers Ryan Ludwick and Rick Ankiel, snapped a 14-inning scoreless slump against Milwaukee pitching in the sixth on Nick Stavinoha's RBI single and a run-scoring groundout by Colby Rasmus. The Cardinals have lost six of eight.
"We had a lineup in there that can win the game, but we didn't," manager Tony La Russa said. "It's a rough time, so we've just got to play our way through it."
Parra worked around his fourth four-walk game of the season to go with five hits, allowing two runs in his fourth straight six-inning stint. The Cardinals stranded two in the first, second and sixth against Parra, who has walked 26 in 43 1-3 innings.
Todd Wellemeyer (3-4) walked seven, two more than his previous career worst. He walked Parra, an .077 hitter, to start the fourth, and hit Hardy and Parra in the sixth.
"They were either perfect pitches or they were not even close," Wellemeyer said. "I mean, I hit the pitcher on his foot on a 1-2 changeup. That shouldn't happen."
Despite those woes, Wellemeyer didn't allow a hit his last 4 2-3 innings after the Brewers batted around in a the first while extending him for 41 pitches. He retired the side in order in the third, fourth and fifth with the help of two double plays.
Wellemeyer has allowed 11 runs in 12 2-3 innings his last two starts but worked seven strong innings in the two starts before that. He said he needed to streamline his delivery.
"I got a little out of whack today," Wellemeyer said. "I figured it out, but it was a little too late."
Hardy's bases-loaded, two-run single opened the scoring on Wellemeyer's 30th pitch of the first, and Kendall's two-run single later in the inning also came with the bases loaded. Kendall also singled in the eighth and is one away from 2,000 career hits.
The first two Brewers reached in the eighth against Boyer, a right-hander, before Fielder hit his ninth homer over the right-field wall. Boyer said he wasn't surprised he was allowed to pitch to the left-handed hitting Fielder, but disappointed he served up a fat pitch.
"It was right over the middle, right in the heart of the plate," Boyer said. "I did him a favor, so that was that."
Wellemeyer is 0-3 with a 5.97 ERA in 11 career appearances against the Brewers, four of them starts. They're the only NL Central team he hasn't beaten. ... Lou Brock replica statue day attracted near-sellout attendance 43,042. ... Brewers 2B Rickie Weeks departed with a sore left wrist after striking out to open the game and will fly to Phoenix Monday to visit a hand specialist. ... Parra evened his career record at 13-13. The Brewers are 3-5 in his starts this season. ... Ryan Braun is 7-for-10 against Wellemeyer. ... The Brewers are 7-0-2 in their last nine series after losing the first four. ... Khalil Greene is in a 2-for-22 slump after going 0 for 4.