MIAMI — Rookie Jace Peterson hit a grand slam for his first major league home run, and the Atlanta Braves overcame another tape-measure shot by Giancarlo Stanton to remain undefeated this year at Marlins Park by beating Miami 5-3 Saturday. Major league RBIs leader Stanton hit his third long homer in as many games, a solo shot into the upper deck in center field, where a spectator made a one-handed catch five rows in front of the 502-foot sign. Stanton homered into the TV camera well in center field Friday, and pulled a drive out of Dodger Stadium on Wednesday.