Daniel Murphy hit a two-run single, and Fernando Tatis also drove in a run to help the surging Mets, who have won eight of nine and 11 of 14. They remained 1 1/2 games ahead of second-place Philadelphia.
Braves starter Jair Jurrjens (11-9) gave up six runs -- four earned -- and six hits in five innings.
Pelfrey walked three and struck out three in his 42nd major league start. He threw 108 pitches and retired his final 11 batters in a game that lasted just 2 hours, 8 minutes.
The key inning for Pelfrey was the sixth, when Atlanta loaded the bases with nobody out on a bunt single followed by two walks. But the 24-year-old right-hander limited the damage.
One run scored on a double-play grounder by cleanup batter Brian McCann, and another on a wild pitch that cut New York's lead to 6-3. Pelfrey got Mark Kotsay on an inning-ending flyout and did not allow another base runner the rest of the way.
Wright hit his 24th homer leading off the fifth, making it 6-1, and the Mets never had to use their shaky bullpen, which is missing injured closer Billy Wagner.
The Braves have lost nine of 10, falling a season-worst 15 games under .500.
Argenis Reyes' single and consecutive two-out walks by Jurrjens in the first brought up Murphy, who fouled off three two-strike pitches before grounded a single through the middle.
It was the latest example of savvy hitting by Murphy, a surprising rookie who spent most of the season at Double-A Binghamton before getting called up from Triple-A on Aug. 2.
It also was another bases-loaded hit for the Mets, who snapped a 3-for-42 slide with the sacks full on Carlos Delgado's go-ahead double in the eighth inning Tuesday night.
Tatis then hit a slow roller toward third. Chipper Jones came in and gloved the ball but threw wildly to first. Tatis was credited with an RBI infield single, and Jones was charged with an error that allowed another run to score.
Brian Schneider reached on a throwing error by shortstop Yunel Escobar and Pelfrey hit the next pitch through the right side for his seventh major league hit and second RBI.
Atlanta trimmed its deficit to 5-1 on Gregor Blanco's two-out RBI single in the third.
