NEW YORK -- Had heavy rains begun blanketing Citi Field just before Tuesday's game rather than just afterward, the outcome might have been a bit different. An already slow infield would have been slower. And some of the seven ground-ball hits that Derek Lowe allowed in the fourth inning might have stuck on the grass.

As it was, a couple of the balls scooted past gloves, one ricocheted off Lowe's left thumb and the rest bounced cleanly into the outfield. On another day, all the ground balls may have constituted a sinkerballer's dream. But on this day, sprinkled between hard hits from Gary Sheffield and former Braves outfielder Jeff Francoeur, the bouncing balls became Lowe's undoing.

So consistently strong throughout the past month, Lowe allowed eight runs in the inning, sending the Braves reeling to a 9-4 loss to the Mets.

"Not good," was how Lowe put it. "That should sum it up -- not good."

Yet manager Bobby Cox was not so convinced. The Braves signed Lowe to a $60 million contract this past offseason to induce ground balls, and he did so Tuesday with remarkable efficiency. Eight of Lowe's first nine outs were recorded on the ground, and that trend did not stop in the fourth.

"I don't know if he struggled or not," Cox said, disregarding the box score.

Lowe knew. He knows that ground balls are only ground balls if they are also easy outs, and none of the Mets' hits in the third inning could be considered such. Angel Pagan's shot to open the inning was hit so forcefully that after it glanced off Lowe's finger, Cox and the team's training staff spent more than a few moments discussing his health. And the rest of the ground-ball hits were struck hard enough to wriggle through the infield.

None were hit right at the infielders, and that was Cox's point when he said, "You'd need another two guys on the infield to catch them tonight." But correct procedure was little solace to Lowe.

"Hitters will tell you how good your stuff is," Lowe said. "There weren't a lot of positives."

What Cox's reasoning also did was keep him immune to the fact that the game was slipping away. Staked to a 4-0 lead over the first three innings, the Braves lost all that and then some while Lowe struggled through the fourth. But Cox, seeing ground ball after ground ball, kept telling himself that Lowe was one pitch away from escaping the inning.

"You can't second-guess that," Cox said. "I left him in for the ground ball, and he got it."

Yet what run-scoring hits by Francoeur and Fernando Tatis and Anderson Hernandez also did was serve to fatigue Lowe. His pitches, for a sinkerballer, were somewhat flat. And by the time the 12th batter of the inning came to the plate, Cox had finally seen enough.

Kris Medlen struck out five over 2 1/3 innings of shutout relief, but the Braves could not come back against the Mets.

"When you put an inning like that together and keep a pitcher out there almost 20 to 30 minutes, it's going to tax him a little bit," Sheffield said. "He wasn't able to go to certain pitches, and he left a lot of balls up after that."

And so it was that the erratic Oliver Perez outpitched the consistent Derek Lowe, despite a first few innings that told a rather opposite story.

It was the Braves who scored early, on Matt Diaz's three-run home run in the second inning and Adam LaRoche's solo shot in the third. The latter hit was even enough to wash away the bad taste of losing Martin Prado, who started at first base but left after one at-bat, after suffering a recurrence of the headaches that have plagued him since Saturday.

The Braves would have liked to have scored more against Perez, or against a Mets bullpen that included such names as Elmer Dessens and Brian Stokes. They did not. But that could not have disappointed them as much as Lowe's performance against the Mets' lineup, which was missing David Wright, Jose Reyes, Carlos Beltran and Carlos Delgado -- among others -- due to injury.

The pitching matchup was in their favor, and the general logic of things said that the streaking Braves had an awfully good chance to upend the struggling Mets -- who are all but playing for 2010.

Instead, the Braves lost, the Phillies, Marlins and Rockies won, and the Braves gave back valuable ground in both the Wild Card and divisional races. Not good, as Lowe might say.

"You feel like you're going to get out of it at some point," Lowe said. "There's no way you think it's just going to continue to go like it is, and it did."