Thanks in large part to an 11-strikeout performance from starter Marco Estrada, the Brewers clung to a 4-3 lead after six innings.
That lead evaporated in the top of the seventh, which started with a single by shortstop Clint Barmes, who reached second on Ryan Braun's fielding error. The Pirates tied the game in the next at-bat, when reliever Kameron Loe fielded Josh Harrison's bunt but threw the ball wide of first base, allowing Barmes to score.
Two batters later, Harrison gave the Pirates the lead for good, racing home on a passed ball that catcher Martin Maldonado admitted he should have caught.
"Nobody wants to make mistakes," Maldonado said. "We're there to try to do our job. Those mistakes are a part of the game. They're going to come along. We have to keep performing after that."
Unfortunately for the Brewers, those mistakes came late in Saturday's game, and although they had three innings to make a comeback, they were unable to do so.
The mistakes also negated another good performance from Estrada, who remains winless in nine starts despite pitching well most of the season.
Estrada set the tone for his outing early, striking out the side in the first inning, as seven of the first 10 Pittsburgh batters went down on strikes. Through five innings, Estrada made just one major mistake, when he left an 0-2 delivery to Pirates center fielder Andrew McCutchen out over the plate in the top of the third inning. McCutchen sent the pitch over the fence in center field for a two-run homer, his 20th of the season.
"I went away from our game plan and decided to throw a fastball away," Estrada said. "And I shook to it, which I shouldn't have done that, and I got hurt for it. I can't be doing stuff like that. I got to stick to the game plan and try to make pitches."
The 29-year-old right-hander didn't find trouble again until the sixth inning, when he surrendered one run on three singles. Loe came on to escape the inning without any more damage, and although Estrada was disappointed in the way his night ended, he was pleased with his overall effort.
"I feel like I'm locating really well," he said. "I'm not looking for strikeouts. I've been working really hard on trying to get ground balls, and I think I did that today. But I'm trying to keep the ball down and make pitches, and if I strike someone out, great."
Early on, it also appeared Estrada would have the run support he needed to earn his first win of the season, as the Brewers posted two runs in back-to-back innings to build a 4-2 lead.
But Pirates starter Kevin Correia settled in after the third and set down the Brewers in order in three straight innings before leaving the game. Despite his early struggles, he said he was confident Pittsburgh could make up for it if he limited the damage.
"This is a weird place to pitch, it's kind of like Colorado -- you know there's going to be runs scored," Correia said. "I knew four wasn't going to be enough to beat us, and I was able to hold it right there."
With just two games in the books after the All-Star break, Roenicke had yet to hit the panic button after Saturday's loss. Similarly, Estrada said he feels the team is playing good baseball, but "things haven't really gone our way with close games."
Both player and manager agreed the Brewers should have won Saturday, though it's getting late in the season to keep letting wins slip away.
"It's one game," Roenicke said. "We bounce back tomorrow and play a good game, we're fine. But we talk about this all the time, and you can't let games get away from you when you should win -- not if you're going to win a division."