Atlanta, hurt early by a four-base error on a fluke play, saw Joe Pittman single home San Diego's tie-breaking run in the top of the ninth.
A walk and a sacrifice preceded Pittman's single off Rick Camp (11-11) and made reliever Gary Lucas, 0-10 coming in, a winner. Camp lost on a complete-game six-hitter.
In the third, Gene Richards hit a fly that left fielder Terry Harper gloved just inside the foul line; Harper's momentum took him four strides into foul territory and hurtling over a fence into the Padres' bullpen. The ball popped free and umpire Ed Vargo ruled fair ball, no catch, as Richards circled the bases.
The Braves didn't fault Vargo. "A judgment call," said Manager Joe Torre. Added third baseman Jerry Royster. "He's got to show the ball. I think if the ball was fair the umpire was totally right."
The Padres made it a 2-2 game with an unearned run in the seventh.
With just seven games to play, all on the West Coast, Royster -- filling in for Bob Horner (left elbow strain) more than a week now -- said Atlanta could not afford any more losses. "The Giants are playing better than us or the Dodgers," he said. "A loss tomorrow (Monday night) in San Francisco would be deadly."