ATLANTA -- Ervin Santana has no trouble summing up the collapse that ended Atlanta's postseason hopes.
"As a pitcher, we have our confidence up, but you either have to throw a complete game shutout or something like that to get a win," he said. "It's very tough."
A half-game out of first place in the NL East on July 29, the Braves have gone 18-30 since then to fall 15 back of Washington. Atlanta was eliminated from the wild-card chase when Pittsburgh beat Milwaukee 1-0 earlier Sunday.
Santana (14-10) said it's hard on pitchers to keep games close when the offense struggles so badly to produce.
"If you are a starting pitcher, you are going to have that in your mind when you see things like this and we don't score any runs," Santana said. "It's tough for us because when we're playing this, if you give up two or three runs and you know it's going to be a tough game."
The Braves lost for the 14th time in 18 September games as deGrom struck out 10 in six innings to extend his impressive streak since June 21.
In his last start, de Grom (9-6) tied the single-game major league record by striking out his first eight batters. Against Atlanta, the shaggy-haired right-hander struck out eight of the first 11 batters he faced.
"I was just trying to stay within myself early on and then if I needed, try to throw it by somebody with a little bit on it," deGrom said. "I was actually trying to do that consciously. That was the game plan."
DeGrom allowed three hits, three walks and two runs -- one earned -- as he threw 63 of 100 pitches for strikes. In his last 15 starts, the rookie is 9-2 with a 1.90 ERA over 99 1/3 innings.
DeGrom, who retired the first 12 hitters he faced, also used his bat, earning his second career RBI with a squeeze bunt that put New York ahead 6-2 in the sixth.
The light-hitting Braves dropped to 8-60 when scoring two runs or less and got swept for the seventh time this year in a series of three or more games.
Atlanta began the day ranked next-to-last in runs scored in the majors and was third in the NL in strikeouts.
Shortstop Andrelton Simmons said it was hard to believe the team has been such a mess offensively.
"The whole year we knew we were struggling at the plate to score runs, but we were hopeful that it was going to turn around," Simmons said. "You try to grind it out. It never happened."
The Mets went up in the first on Daniel Murphy's RBI groundout and 2-0 in the second on Tejada's sacrifice fly.
Santana gave up six hits and five runs with two walks and four strikeouts in five innings.
But deGrom, who faced eight batters in the inning, struck out Phil Gosselin to leave the bases loaded.
It was a scene Santana, a 10-year veteran in his first season with Atlanta, has seen too many times. The Braves dropped to 1-12 when scoring two runs or less over their last 20 games.
"Seriously, I don't know what to tell you," Santana said. "From a pitching standpoint, we do our job and we don't score any runs. I don't know. I don't know. Seriously, I don't know."
Mets: RHP Bartolo Colon (14-12) is 2-4 with a 3.07 ERA in six career starts against Washington. The NL East champion Nationals begin a three-game series in New York on Tuesday.
Braves: RHP Aaron Harang (11-11) is 16-7 with a 4.15 ERA in 27 career starts against Pittsburgh. The Pirates open a four-game series Monday at Turner Field.
The Mets swept a three-game series at Turner Field for the first time since Aug. 31-Sept. 2, 2007. New York won 10 of 19 games this year for its first season series victory against the Braves since 2006.