Howard led off the eighth with a double to right. With one out, Ibanez singled to right. Joe Mather's throw beat Howard to the plate but short-hopped catcher Brian McCann, who couldn't hold on as Howard scored the go-ahead run.
Braves reliever Cristhian Martinez retired all 12 batters he faced and had a two-run double. He took over for Brandon Beachy, who left with a left oblique injury after two innings.
Antonio Bastardo (2-0) struck out Freddie Freeman with the bases loaded to end the seventh.
Ryan Madson pitched the ninth for his sixth save. With pinch-runner Jason Heyward on second base, Madson struck out Dan Uggla to end the game.
Howard's three-run homer in the first drove in Shane Victorino and Placido Polanco, who had singles.
Martinez had four strikeouts in four perfect innings. He delivered the surprise of the night when he drove in two runs with a double off Cole Hamels in the fifth for the first hit and RBIs of his career. The double, which drove in Alex Gonzalez and Mather, tied the game at 3.
With two outs in the sixth, Gonzalez singled and moved to third on Mather's double. With pinch-hitter Diory Hernandez at the plate, Hamels threw a wild pitch, allowing Gonzalez to score for a 4-3 lead.
The Phillies pulled even in the seventh when Jimmy Rollins hit a two-out double off Eric O'Flaherty (1-2) and scored on Victorino's single.
O'Flaherty and McCann began to leave the field on what they believed was a called third strike on Victorino, but umpire David Rackley called the pitch a ball. Victorino then tied it with his single to center, leaving McCann complaining to the umpire.
Chipper Jones had a run-scoring single in the first to drive in Martin Prado, who had three hits. Gonzalez also had three hits for Atlanta.
Beachy was pulled when he had discomfort making his warmup throws before the third inning. There was no immediate update on the severity of his injury.
NOTES: Braves pitching coach Roger McDowell returned from his two-week suspension for making homophobic comments and crude gestures toward fans in San Francisco. ... Victorino has a 15-game hitting streak. ... Martinez was 0 for 8 in his career at the plate before his double. ... Prado was thrown out trying to steal second to end the third inning. The Braves are last in the major leagues with only six stolen bases - on 18 attempts. Prado has been caught on four of his five attempts. ... LHP Mike Minor and RHP Rodrigo Lopez are the top candidates to be recalled from Triple-A Gwinnett if Beachy is placed on the disabled list. ... Heyward missed his third straight with inflammation in his right shoulder, but he entered the game as a pinch-runner in the ninth.
