SAN FRANCISCO -- In an epic duel between a catcher's speed and an outfielder's arm, an infielder prevailed Tuesday night.

Converted third baseman Hernan Perez, a late-game defensive replacement, threw out Nick Hundley at the plate from right field to preserve a one-run lead in the eighth inning, helping the Milwaukee Brewers hold on for a 4-3 victory over the San Francisco Giants.

Ryan Braun and Travis Shaw drove in runs in a two-run seventh for the Brewers, who rallied from a 3-2 deficit to win for the third time in five games on their nine-game trip.

"We're at a point in the season where we're going to say every win is big," said Brewers manager Craig Counsell, whose club kept pace with the first-place Chicago Cubs atop the National League Central, remaining 2 1/2 games back. "We're chasing. Every win is important."

Brandon Crawford had a two-run homer for the Giants, who had won five straight at home over the Brewers.

"Big home run. We're down a run and he hits a home run that put us ahead," Giants manager Bruce Bochy said. "He's been getting some big hits for us lately. I'm glad to see him getting back on track."

After the Giants lost their one-run lead in the seventh inning, they nearly drew even in the eighth against right-hander Anthony Swarzak.

Pinch-hitting for Ryder Jones, Hundley singled with one out and advanced into scoring position with two outs when Swarzak walked pinch hitter Hunter Pence.

Denard Span, who twice earlier in the game failed with the bases loaded, grounded a single to right field, but Perez's accurate throw to the plate easily beat Hundley for the inning-ending out.

"I knew it was Hundley at second base. He's not very fast," Perez said of the thought process that led to his first assist as a right fielder this season. "It was a slow hit, so I tried to get it as quickly as I could and make a good throw."

Perez, who has played 240 of his 392 career games at second or third base, was mobbed by teammates when he reached the dugout steps a few seconds later.

"It's the same (as hitting a game-winning home run) because you are the hero," he said. "You are the guy who did the play that won the game. That's a great feeling."

Bochy was surprised with the outcome of the game's most critical play.

"The runners get a good jump (with two strikes, and) it wasn't hit real hard," he said. "You give their right fielder credit. He came in, got rid of it. It was kind of an awkward throw; it looked like it bounced a couple of times, but right on the money. They executed."

Closer Corey Knebel pitched a scoreless ninth for his 27th save, fanning Buster Posey for his franchise-record 100th relief strikeout of the season to end it.

Brewers catcher Manny Pina threw out Kelby Tomlinson trying to steal after the Giants second baseman opened the ninth with a single. It was Pina's second gun-down of the night.

"Good defense in this place is important," Counsell said. "We played a good defensive game tonight, that's for sure."

The Brewers trailed 3-2 after Crawford's homer, his 11th of the season, before Eric Thames drew a one-out walk from Giants right-hander Albert Suarez (0-3) to open the seventh inning.

Neil Walker followed with a double, after which Thames scored from third on Braun's game-tying sacrifice fly.

Shaw then grounded a double into the right field corner, scoring Walker with the go-ahead run.

Right-hander Jeremy Jeffress (1-0), who pitched a scoreless sixth inning, got the win.

Walker and Eric Sogard had two hits apiece for the Brewers (66-61), who are three games behind the Colorado Rockies (68-57) in the race for the second NL wild card.

The win was the 200th of Counsell's managerial career.

Pablo Sandoval and Gorkys Hernandez had two hits each for the Giants, who fell to 3-3 on their seven-game homestand.

Neither starting pitcher got a decision.

Seeking his ninth win of the year, Giants right-hander Jeff Samardzija left with a 3-2 lead after six innings, having allowed just two runs (one earned) and six hits.

Brewers starter Jimmy Nelson failed in his fourth straight try to pick up a 10th victory. He gave up three runs and seven hits in five innings.

Both starting pitchers failed to help themselves with the bat, short-circuiting potential big innings early.

The Brewers scored single runs in the second and fourth innings to take 1-0 and 2-1 leads. But in both cases, the uprising ended when Nelson made an out (a strikeout and a groundout) with a runner in scoring position.

The Giants countered Milwaukee's second-inning run with one of their own on an infield single by Hernandez. Nelson then struck out Samardzija with one out and the bases loaded before getting Span to ground out to prevent further scoring.

The same inning-ending scenario played out two innings later when Samardzija again struck out with the bases loaded and one out. Span then lined out as Nelson retained his 2-1 lead.

NOTES: The Brewers won for just the 11th time this season when not hitting a home run in the game. ... Giants RF Hunter Pence (tight left hamstring) was scratched from the starting lineup shortly before first pitch. He was replaced in right field by Gorkys Hernandez. Pence pinch-hit in the eighth inning and drew a walk before leaving for a pinch runner. ... Giants RHP Johnny Cueto (strained flexor tendon) pitched three shutout innings in a rehab start for Triple-A Sacramento against Albuquerque. He allowed three hits and struck out one while throwing 47 pitches. ... Giants 2B Joe Panik (concussion) played the first five innings in the same game at Sacramento, going 0-for-2 with a strikeout. He is scheduled to play seven innings for Class A San Jose on Wednesday night.