Martinez struggled in his first start in more than a month, allowing four runs in three innings in a 5-3 loss to the Pittsburgh Pirates.
When he came out of the game, Martinez sat in the dugout, head in his hands, and manager Willie Randolph put an arm around him.
"My pitches weren't there. That was the biggest frustration," Martinez said. "I was about to snap and let it all out. Thank God Willie was there. I felt like crying at that time."
Martinez (9-6) had been on the disabled list because of a strained right calf since Aug. 14, and Randolph said he would be limited to 60-to-80 pitches.
He threw 68 pitches and gave up six hits, walked one, hit a batter and made a throwing error. He struck out four.
"I didn't see the results I was expecting," Martinez said. "When you come off so many days without throwing the ball, you want to make a statement. I wanted to do a little bit better. My physical body didn't feel quite as well as I was expecting for the time being. I can't expect to be 100 percent fine. I still have plenty of time to do it."
Randolph said Martinez was healthy and would take his next turn in the rotation.
"I thought he did pretty well, actually," Randolph said. "He's a competitor. He's a warrior, and it didn't work out like he wanted. He's a little frustrated."
Mets pitching coach Rick Peterson said he was not alarmed, saying Martinez showed good command of all four of his pitches.
"I thought his stuff was good," Peterson said. "He just made some mistakes. You've got a young club that swings the bats decently and aggressively, and if you make some mistakes out over the plate they're pretty good at hitting those pitches."
After the game, the Mets missed a second chance to clinch its first division title in 18 years when Philadelphia held on for a 4-3 win at Houston. Many of the Mets watched on television as Houston's Humberto Quintero hit into a game-ending double play.
"Some of us I think want to try to win the game on the field," catcher Paul Lo Duca said. "It would have been nice. We're not backing into anything. We've won a lot of games, and we've played well. But still, hopefully, we will take care of it tomorrow night."
Paul Maholm (8-10) allowed one run and two hits in seven innings as the Pirates beat the Mets for the second time in seven tries this season. Maholm, who walked three batters and hit three, is 4-0 in his last seven starts.
"Them being in first place and if they win they get to celebrate, that was another incentive to go out there and pitch good, because I don't think there's a player in here that wants to watch them celebrate on our field," Maholm said.
Salomon Torres pitched the ninth for his eighth save -- all coming in Pittsburgh's last eight wins.
"It shows the way we've been playing," said Bay, whose team is 31-27 since the All-Star break after a 30-60 start. "Regardless of who we're playing, we are playing good baseball. It's somewhat gratifying against teams like this to stack yourself up to see how you have been doing."
Pittsburgh jumped on Martinez in the first inning when Bay doubled home Jack Wilson and Freddy Sanchez. Sanchez went 2-for-4 and is hitting .340 but lost his lead in the NL batting race to Florida's Miguel Cabrera, who had three hits and is batting .342.
The Mets, who dropped to 23-19 against left-handed starters, did not get a hit until the fourth and did not score until the fifth, when two batters were hit before Reyes' RBI single.
The Mets' next chance to clinch was Saturday afternoon, when the Phillies play a day game at Houston. If Philadelphia wins, New York could clinch with a win over the Pirates on Saturday night.
"However it gets done, we want it done with, so Willie can start with his planning," outfielder Cliff Floyd said. "We're very fortunate to be in this position. There's lots of teams battling right now playing for their lives. You turn on the ESPN and you see how this team has to win or that team has to win. We're fortunate the position we are in."
- Mets C Paul Lo Duca was ejected from the game when he argued with umpire Jeff Kellogg after being called out on strikes to end the fifth.
- Sanchez has 48 doubles this season, setting a club record for right-handed hitters.
- Martinez finished the game with 2,990 career strikeouts.
- The Mets are 11-10 in games started by Martinez.