NEW YORK -- After winning two riveting and tightly-contested games against the Braves on Friday night and Saturday afternoon, the Mets were undermined Sunday by their own pitchers -- understudy Jose Lima and reliever Bartolome Fortunato -- and, they thought, by a questionable call.

Their starting-pitching problems might have worsened when Lima performed ineffectively in a 13-3 loss that denied them their first sweep of the Braves since September 2003 and ended their wining streak at four games. But they also attributed an element of the most lopsided of their 10 defeats to home-plate umpire Angel Hernandez.

Whatever the cause, the loss put a stain on what had been a grand weekend for them. They had a chance to put the Braves 10 games behind them and to demonstrate they could win a poorly-pitched game.

The Mets believe the tenor and the positive tension of the game changed prior to and during the second inning, when the Braves scored two runs, the first run on a close play at the plate. Hernandez ruled Braves catcher Brian McCann avoided an attempted tag by Mets catcher Paul Lo Duca.

Lima alleged before the inning began that Hernandez told the Mets' substitute starter he wouldn't be afforded the same strike-zone benefit of the doubt afforded Braves starter John Smoltz. And those two developments and a balk called early in the inning "changed everything," Lima said. "It changed my day and the Mets' day ... in a bad way."

In the end, Lima's first start did more to exacerbate the Mets' pitching problems than solve them. Pitching in place of injured John Maine, who was to have started in place of injured Brian Bannister, Lima filled out his bingo card, as they say in the dugouts, in his first big-league start this season. The 33-year-old veteran of 10 Major League seasons and 231 Major League starts, allowed five runs, seven hits, four walks and a home run, threw a wild pitch, hit a batter and balked -- all in five innings.

But his postmortems focused on the balk, Hernandez's strike zone and the tag.

"I could have come out of that inning, nothing-nothing," he said. "But you know what happened."

And what happened was this, according to Lima. As he walked to the mound to start the second, he engaged Hernandez in conversation about the strike zone. "He said to me, 'You're not going to get those three or four extra inches. You're not John Smoltz.'"

Lima, as outspoken as any player, said, "He treated me like a rookie. He knows me. He knows I've been here. He treated me like I was new."

What effect the strike zone had on Lima, he didn't specify. But he did endure an ugly inning. McCann led off with a single. Second-base umpire Sam Holbrook called Lima for a balk, with Brian Jordan batting, the third balk against Lima in 1,550 1/3 big-league innings. Jordan hit the balk pitch to shortstop, and the Mets thought they turned a double play. Instead, McCann was on second and, after Jordan struck out, advanced to third on Ryan Langerhans soft single to right.

Smoltz, who later successfully squeezed in a run in the fifth, missed a squeeze sign but then hit a tapper in front of the plate. Lo Duca fielded it with his bare hand and lunged at McCann. Replays appeared to indicate Lo Duca had tagged the runner. And McCann later acknowledged to a Mets batter that he had been tagged. But Hernandez called him safe and immediately ejected Lo Duca once the Mets catcher slammed the ball to the turf while protesting.

"I spiked it like Ickey Woods," Lo Duca said, before acknowledging, "I lost control of my emotions, and I regret that. But I tagged the guy, and he blew the call. I'm not going to sugarcoat it. It was a big part of the game. The balk call amazed me, too."

"I get that double play, none of that happens," Lima said. "Lo Duca is still in the game and we get a run the next inning from Carlos [Beltran, who hit a solo homer in the third after Jordan hit one off Lima] and maybe everything is good."

Or maybe not. A subsequent single by Edgar Renteria scored Langerhans, and after the offsetting home runs in the third, the Braves scored twice in the fifth. With Smoltz giving the Mets nothing -- they had three hits in six innings against him -- more Braves' run would be too much. And Fortunato allowed eight in his 1 1/3 innings.

The calls diverted the Mets' attention from their own offensive shortfall. They scored their second run when they were down 13, and their third run was unearned.

"Maybe we lost a little focus after all that stuff early," manager Willie Randolph said. "We didn't play well. And Smoltz is never easy."