ATLANTA (Reuters) - Atlanta rookie Freddie Freeman delivered a game-winning two-run single in the bottom of the ninth inning as the Braves rallied to a comeback 5-4 victory over the San Francisco Giants on Monday.

"It's huge," Freeman told reporters. "Especially when you're in a playoff race and you're playing a team right behind you in the Wild Card (race).

"To win the first game of the series is always great."

The Giants, who also slipped 2.5 games off the lead in the NL West, had been well set up by starter Madison Bumgarner, who conceded only two runs in a solid seven-inning performance.

Mike Fontenot added a blast in the eighth against Atlanta starter Tim Hudson who pitched eight innings in a no-decision.

Martin Prado singled in a run in the ninth to close the gap for Atlanta, before Wilson walked a batter to load the bases.

Freeman then came through with the winning hit with the Braves down to their final out, casting a cloud over the Giants' hopes in the Wild Card race.

Reliever Cristhian Martinez pitched the ninth for the Braves as they recovered from two straight defeats.

"That's a helluva comeback there," said Braves manager Fredi Gonzalez. "These guys, we battled the whole game."

Jose Constanza went 3-for-3 with an RBI for Atlanta, while Dan Uggla got a hit one game after ending his league-high 33-game hitting streak.

(Writing by Jahmal Corner in Los Angeles; Editing by Ian Ransom)