ATLANTA -- The Atlanta Braves pulled off their third walk-off victory in the past five games, and this time Matt Kemp was the hero.

Kemp hit a two-run homer in the 11th inning off San Francisco Giants reliever Cory Gearrin to give the Braves a 5-3 win Wednesday night.

Nick Markakis walked with one out, and Kemp connected on an 0-1 pitch for an opposite-field homer to right field.

It was Kemp's 12th homer of the season and his seventh career game-ending blast.

The Braves lead the National League with six walk-off wins and have also won six road games with runs in their last at-bat.

"Like I keep saying, they never quit," Atlanta manager Brian Snitker said. "They just grind through games. They keep coming at you."

Hunter Pence's fifth homer of the season, over the center field fence on a first pitch from Atlanta closer Jim Johnson with one out in the ninth inning, tied the game and cost Sean Newcomb his first major league victory.

"It's another tough loss for us," Giants manager Bruce Bochy said. "It's our third comeback on the road trip and we've lost them all."

Newcomb allowed three hits and one run over six innings while lowering his ERA to 1.96.

"He was really good again. You've got to like what you see out of that kid," Snitker said. "I wish we could have got him that first win."

A downpour shortly before the scheduled first pitch delayed the start 75 minutes, and the game didn't end until after midnight ET. Monday's series opener began 44 minutes late because of rain.

In the second inning, the Giants grabbed a lead when Brandon Belt's two-out triple down the right field line scored Pence, who had singled.

The Braves went ahead in the fourth as Matt Adams followed a single by Markakis with a homer to right-center field on a 2-2 pitch from Giants starter Jeff Samardzija.

Tyler Flowers connected with the bases empty in the seventh, but a wild pitch in the eighth made it a one-run game.

Newcomb, who walked one and struck out three, retired his last 13 batters before being pulled after 80 pitches. The Braves' bullpen couldn't protect the lead, though.

"Probably next time he'll go back out," Snitker said. "I just felt he had done his job."

The left-hander lost his first two starts despite giving up just three runs over 12 1/3 innings.

Samardzija allowed three runs on six hits in seven innings. The right-hander walked none and struck out eight, throwing 60 of his 79 pitches for strikes.

"He threw a beautiful game," Bochy said. "Really impressive and another quality start for us. We have three here and one win. That's disappointing."

Flowers' sixth homer, which came on a 2-1 pitch, hit the top of the right field fence and bounced off the foul pole screen. An umpire review confirmed the home run.

Adams has hit 11 of his 12 homers since joining the Braves on May 21. He has 29 RBIs in 30 games with Atlanta.

"He just keeps going," Snitker said. "You feel good every time he comes to the plate. He's making the most of a really good opportunity for him."

Arodys Vizcaino threw a wild pitch following a triple by Denard Span to give the Giants their run in the eighth.

Luke Jackson, who got the final two outs in the top of the 11th around a walk, got credit for the victory, improving to 2-0. Gearrin is 1-2 with the loss.

NOTES: Braves 1B Freddie Freeman, who broke his left wrist when hit by a pitch May 17, is ahead of schedule in his recovery and hopes to return around the All-Star Game, playing third base. "I'm 100 percent go on it," said Freeman, who suggested the switch that would allow 1B Matt Adams to stay in the lineup. ... Giants 3B Eduardo Nunez sat out for the fifth time in six games and also will miss Thursday's series finale because of a sore hamstring. Manager Bruce Bochy said Nunez is headed to the disabled list if he doesn't show improvement Friday, when the Giants return to San Francisco. ... Braves LHP Jamie Garcia (2-5, 3.59 ERA) will oppose Giants RHP Matt Cain (3-6, 4.99) on Thursday. ... Giants LHP Madison Bumgarner, injured in a dirt-bike accident April 20, threw 35 pitches Wednesday in his second simulated game at Scottsdale, Ariz. He is scheduled to pitch three innings in a rookie-level Arizona League game Sunday.