Wasting two homers by David Wright and a strong start from Oliver Perez, the Mets lost for the ninth time in 30 games. Their lead could be cut to one game - two in the loss column - if second-place Philadelphia beats Milwaukee in the second game of a day-night doubleheader Sunday. The Phillies won the opener 7-3.
The Mets squandered a seven-game cushion with 17 to play last year, letting Philadelphia charge past them for the division title in one of the worst collapses in baseball history.
Desperately trying to erase those painful memories, New York had 17 games remaining coming into this series and dropped two of three to the fourth-place Braves (67-83).
Missing injured closer Billy Wagner for the rest of the season, the bullpen failed to hold an eighth-inning lead for Johan Santana in the opener of Saturday's doubleheader and flopped again Sunday.
Ayala (2-9) began the ninth with a 4-2 lead and allowed consecutive singles to Casey Kotchman and pinch-hitter Kelly Johnson. Norton then drove a full-count delivery into the Mets' right-field bullpen - appropriately - for a 5-4 Atlanta edge.
It was Norton's third pinch-hit homer this season.
After Ayala was lifted, the Braves tacked on two more. Gregor Blanco hit an RBI double off Pedro Feliciano, and Corky Miller's sacrifice fly against Brian Stokes made it 7-4.
Jorge Julio (2-0) worked a scoreless eighth for the win.
The Mets have 27 blown saves this season. They began the day tied for third-most in the majors. This was New York's 11th blown save in the ninth inning. They started the day tied for third-most in that category as well, according to the Elias Sports Bureau.
Ayala had been doing a nice job as the replacement closer since being acquired last month in a trade with Washington. He is 7-for-9 in save opportunities with New York.
The Mets tried to make a comeback of their own in the bottom of the ninth, putting their first two batters on. But Mike Gonzalez retired the next three for his 11th save in 12 chances.
Atlanta slugger Chipper Jones had three hits, including an RBI double, in his final game at Shea Stadium, where he's had so much success that he named one of his sons Shea.
The All-Star third baseman, who missed Saturday's doubleheader with a stiff back, finished with a .313 batting average, 19 homers and 55 RBIs in 88 games at the ballpark.
Wright matched a career high with four hits for the Mets. He had three RBIs and hit both homers off starter Jorge Campillo, who lasted 3 2-3 innings.
New York has 14 games left and begins its final road trip of the season Monday night at Washington. That four-game series is followed by three in Atlanta next weekend.
Wright's 12th career multihomer game and third this season gave him a career-high 31 home runs, surpassing last season's total by one. He also hit a two-run shot in the first inning Saturday night.
