MILWAUKEE -- The Milwaukee Brewers had plenty of chances to pull away from the San Francisco Giants Wednesday afternoon, but they never seemed to be able to get that one extra hit that would break things open.

Their luck finally changed in the seventh inning when Chris Carter's sacrifice fly to center drove in what would become the decisive run in the Brewers' 4-3 victory over the Giants at Miller Park.

Four times through the first six innings, Milwaukee put at least two runners on with less than two outs, but each time, those runners were left stranded.

Fortunately, Milwaukee's bullpen was on point, holding the Giants to just a run over the final four innings -- and keeping them scoreless over the final 3 2/3 -- giving the offense time to come through.

Tyler Thornburg (1-0) worked around a leadoff single to keep San Francisco off the board in the top of the seventh while Scooter Gennett drew his second walk off the day to kick off the bottom of the frame against Giants left-hander Javier Lopez (0-1).

Giants manager Bruce Bochy turned to right-hander Cory Gearrin to face Ryan Braun, who singled to left. Both runners advanced during a Jonathan Lucroy strikeout, which brought up Carter.

"In that situation, I had to get the run in," said Carter, who had hit his first home run of the season earlier in the day.

Gearrin got ahead of Carter 2-1 with a steady diet of sliders. He threw a fourth, and Carter got just enough to get it to center, allowing Gennett to score easily and put the Brewers in front.

"It was a good at-bat," manager Craig Counsell said. "It is an at-bat where you have to put the ball in play. It is something he's challenged by occasionally, but he did a nice job of it today. He had a big day for us."

Angel Pagan and Hunter Pence had two hits each for the Giants, who couldn't do much against Brewers right-hander Taylor Jungmann.

Jungmann allowed two runs -- one earned -- on three hits with a pair of walks and a strikeout over five innings of work.

San Francisco starter Jeff Samardzija also went five innings and allowed eight hits with three walks, but held the Brewers to three runs while striking out six.

"He battled well but was off a little bit," Bochy said, "He found a way to keep us in the game, though, and when he left the game, it was tied. Great job on his part, battling with men on base and pitching well in traffic."

A first-inning error on catcher Lucroy allowed San Francisco to take an early 1-0 lead but Milwaukee got it back in the bottom of the inning when Domingo Santana drew a leadoff walk and eventually scored on Ryan Braun's single.

Matt Duffy's leadoff homer in the second put the Giants back in front and Milwaukee responded again, trying the game at 2 on Santana's RBI single.

The Brewers took a 3-2 lead in the third on a solo home run by Carter.

Jungmann gave way to lefty Chris Capuano in the fifth, but he gave up a Pagan triple, and Pagan would tie the game once more by scoring on a sacrifice fly by Buster Posey.

Jeremy Jeffress notched his first save with a perfect ninth.

"We played two good games," Counsell said. "We played a good game yesterday. We played a good game today. I'm happy with how we played the last two days as much as anything. That's a really good team. That's one of the best teams out there. We didn't win the series, which is the goal every time, but the last two days I liked how we played."

NOTES: Giants OF Denard Span was held out of the starting lineup Wednesday after being bitten by a flu bug that has been working its way through the San Francisco clubhouse. Span had gone 3-for-8 with a home run, five RBIs, two runs scored and a stolen base in the first two games of the season. He struck out pinch-hitting for the pitcher in the seventh inning. ... OF Gregor Blanco took Span's place in center field and moved into the ninth spot in manager Bruce Bochy's lineup while LF Angel Pagan moved into the leadoff spot. ... LHP Sam Freeman arrived in Milwaukee, was in uniform and available after he was acquired by the Brewers from Texas for cash considerations. Freeman posted a 5.68 ERA in six relief appearances with the Rangers during spring training.