NEW YORK -- A smattering of boos trailed second-base umpire Dan Iassogna off the field Monday, some two hours after he made the call that may have cost the Mets the game. At the least, it cost the Mets their composure. And six runs. And much of that fell upon the shoulders of Mike Pelfrey.

It was Iassogna's call that haunted the Mets in the aftermath of their 8-6 loss to the Reds. But it was Pelfrey's mound meltdown that caused the most significant damage.

"This is pretty much the first time I've seen that," catcher Rod Barajas said. "He's been great all year not letting calls or anything influence the way he pitches on the mound. I think this time he got a little frustrated and he just made a couple mistakes."

Three mistakes, actually: a two-run single to Drew Stubbs, a two-run double to Corky Miller and an RBI triple to the pitcher, Travis Wood -- all with two outs in the fifth. Moments earlier, Iassogna had reversed home-plate umpire Jerry Meals' original call of a foul tip strikeout of Scott Rolen, ruling that the ball hit Rolen on the right forearm.

Pelfrey -- who later quipped that Rolen has "an acting career" awaiting him in retirement -- disagreed. Manager Jerry Manuel, who was ejected, vehemently disagreed. But the call stood, forcing in a run, while forcing Pelfrey to proceed with the bases still loaded.

At the time, it was but a one-run game. And after Pelfrey popped up Jonny Gomes and struck out Jay Bruce, it appeared that things would stay that way. But Stubbs, Miller and Wood then struck in quick succession, chasing Pelfrey from the game while opening a 7-1 lead.

"He kind of lost it there," Manuel said. "And all that's a part of maturing. I think that's a learning experience for him. I think Mike will grow from these things and be better for it."

For a pitcher who has taken pride in his new-found ability to forget mistakes, Monday's meltdown was certainly troubling. Pelfrey was unable to push Iassogna's call out of his mind. And he was the first to admit it.

"For the first time in over a year," Pelfrey said, "I let my emotions get the best of me."

One other factor contributed to Pelfrey's demise at Citi Field, as well: Joey Votto. One of the few players considered a more significant All-Star oversight than Pelfrey, Votto crushed a solo home run off him in the first, then another off Fernando Nieve in the sixth.

"He doesn't seem like he's afraid to get beat," Votto said of Pelfrey. "He's had a good year thus far. We got to him that one inning and knocked him out. I think that says a lot about our offense in general."

Indeed, the Reds have risen to the top of the NL Central in large part due to their stellar offense, with home run threats -- even at Citi Field -- up and down their lineup. But the Mets have also enjoyed a fine offensive run of late, so it was hardly shocking that they were able rebound with five runs of their own in the fifth.

Pagan, in his final days as the regular center fielder, homered off Wood to spark the scoring. With one out, David Wright -- perhaps the only player in baseball hotter than Votto -- tripled, before Barajas singled in a run and Alex Cora doubled in two more off reliever Jordan Smith.

Just like that, the Mets had moved within a run. But Votto homered to double the lead in the sixth, and the Mets did no more scoring, falling silent amid their own murmurings.

"I still really don't know what happened," Wright said, reflecting on the Rolen play. "If they got it right, I guess that's the important thing."

After the game, Manuel said that the Mets would have some correspondence with Major League Baseball, airing their grievances with the league. But that won't change anything. At day's end, this was a tough game to lose and a tough loss to swallow.

And for Pelfrey, it was a tough lesson to learn.

"He came back and got the next two guys," Rolen said. "We were able to put some good swings and some things together. An interesting call possibly changes the game but it was the right call. I'm happy about that."