"I've had a tough year, not only physically but mentally," he said. "A lot of distractions. I lost my dad, and I'm coming off surgery. I didn't pitch the first half of the season."
Kelly Johnson hit an RBI double off Martinez in Atlanta's three-run first inning, rookie Josh Anderson had three hits, and the Braves won 4-2 Saturday night to end the Mets' three-game winning streak.
Following Philadelphia's 3-2 win at Florida, New York dropped into second place in the NL East, a half-game behind the Phillies.
"The first inning hurt us, and we never overcame that," Mets manager Jerry Manuel said. "We didn't have much going offensively tonight, and that's what hurt us the most. We hit a few balls hard."
After an embarrassing collapse last year in which they failed to hold a seven-game lead with 17 remaining, the Mets held onto first place just one day before giving it back to Philadelphia.
Martinez (5-6) lost his third straight decision, giving up nine hits and four runs in six innings. He made 116 pitches, a season-high.
Mike Gonzalez worked a perfect ninth for his 12th save in 14 chances, helping Atlanta stop its four-game skid.
The Braves' first three batters of the game reached against Martinez, who is 1-3 with a 7.00 ERA in his last five starts. Anderson led off with a single and swiped second before Martin Prado walked on four pitches. Johnson followed with a double to right and Brian McCann drove in Prado with a groundout.
"Maybe I'm not being as aggressive as I should, but when I'm aggressive, I give up homers," said Martinez, whose father died in the Dominican Republic two months ago. "Maybe I think a little too much. I think that might be the reason."
The big first inning was enough for Jorge Campillo (8-7), who allowed two runs and five hits in six innings and won for the first time in eight starts.
Since beating Milwaukee 5-2 on Aug. 3, Campillo had gone 1-3 with a 6.91 ERA over his previous eight turns in the rotation.
"A lot of people thought I was tired, and that's true," Campillo said. "Everybody's tired this time of year."
Campillo stranded a runner at third in the sixth when first baseman Kotchman knocked down Carlos Beltran's hard grounder and beat the speedy center fielder to the bag.
Martinez doubled in two runs in the fifth, but Anderson's sixth-inning RBI single made it 4-2.
Martinez dropped to 11-10 with a 3.70 ERA in 30 career games, 23 starts, against the Braves.
"We got to him early, and I think that's how you've got to win against these guys," McCann said. "You've got to get to them early, make them play catch up."
The Braves announced a season-high crowd of 50,124. ... Braves 3B Chipper Jones was removed from the lineup because of tendinitis in his right shoulder. ... Mets RHP John Maine, on the DL since Aug. 24 with a bone spur in his shoulder, reported no major discomfort after throwing 24 pitches in a simulated game. ... Martinez struck out seven to move within eight of tying former Boston teammate Curt Schilling for 14th place on the career strikeout list with 3,116. ... During an examination by New York's team physician, OF Fernando Tatis, on the DL with a separated right shoulder, learned he might be ready to return in two to three weeks if the Mets make the playoffs.