Melancon (1-1) walked Dan Uggla to open the 10th. B.J. Upton struck out after fouling off an attempted sacrifice bunt. Melancon then hit pinch-hitter Reed Johnson with a pitch, bringing Simmons to the plate.
Simmons, who had three hits and a walk, sent a long fly ball to the gap in right-center. Uggla jogged calmly around third base with the winning run before the Braves raced to celebrate with Simmons near second base.
Anthony Varvaro (3-0) pitched a perfect 10th. Four Braves relievers combined to allow one hit in four scoreless innings in the Braves’ fourth straight win.
Upton hit a two-run homer for Atlanta. Pittsburgh’s Gaby Sanchez and Pedro Alvarez also connected for homers.
The Braves came close to ending it in the ninth. After Justin Upton’s broken-bat single to left field, Freddie Freeman hit a deep fly that center fielder Andrew McCutchen caught at the wall. Grilli walked Brian McCann before striking out Ramiro Pena.
The Braves left the bases loaded in the eighth. Tony Watson walked Chris Johnson. Pena, running for Johnson, moved to second base when Watson walked Dan Uggla. B.J. Upton popped out before Pena and Uggla advanced on Watson’s wild pitch to pinch-hitter Evan Gattis. Watson then issued an intentional walk to Gattis, loading the bases before Simmons grounded out to end the inning.
The Pirates wasted an opportunity against Craig Kimbrel in the ninth.
McCutchen, who had a two-run double in the third inning, hit Kimbrel’s first pitch in the ninth for a single up the middle. With one out, Russell Martin walked. Kimbrel struck out Travis Snider on three pitches and ended the inning on Alvarez’s fly to center field.
McCutchen’s two run double in the third gave the Pirates a 3-0 lead.
Freeman cut the lead to 3-2 when he reached out and slapped a two-run, opposite-field double past Alvarez at third base in the third.
Former Braves draft pick Jeff Locke left the game in the sixth inning with a 4-2 lead after giving up a two-out single to Uggla. B.J. Upton tied the game with a two-run homer to center field off right-hander Ryan Reid.
Locke gave up six hits and three runs in 5 2/3 innings. He matched his season high with seven strikeouts.
Minor allowed four hits and four runs, two earned, in six innings.
Pirates manager Clint Hurdle gave Martin his first career start in right field. Martin, the starting catcher in Monday’s opening game of the series, has appeared in three games at third base this season but no games in the outfield.
The Braves traded Locke to the Pirates on June 3, 2009, as part of a package that sent outfielder Nate McLouth to Atlanta. The Pirates also acquired right-hander Charlie Morton in the deal.
NOTES: The Pirates are off Thursday before opening at series at the Chicago Cubs. Hurdle said he plans to use Francisco Liriano, A.J. Burnett and Locke as his starting pitchers in Chicago. ... Braves manager Fredi Gonzalez said he plans to start Gattis today to give McCann a rest in the day game following Tuesday night’s game. ... The three-game series ends when Braves RHP Julio Teheran faces Pirates LHP Wandy Rodriguez. The game will end the Braves’ eight-game homestand