ATLANTA - Even before his team stepped on the field Friday, Mets manager Terry Collins said it was "pretty obvious" that his sluggish team has been a step slow of late.

"In the NBA, when guys are tired, people go around them," he said. "Football when they're tired, people run by them. When you're tired in baseball, when you need that first step, when you need that hand-eye coordination that's just not there, it's quite obvious."

So perhaps it shouldn't have come as any surprise a few hours later, when the Mets looked wobbly legged and weary, powerless to stop the Braves from rallying for a 2-1 victory Friday night.

Once again, the Mets were betrayed by their shoddy defense, a persistent problem in the first three games of their road trip. Meanwhile, the lineup has scored just twice in that span.

All three games have ended in losses.

Somehow, the Mets (36-33) have maintained a slim lead over the Nationals in the NL East. But it won't last if the Mets continue leaking oil on their tortured road trip.

Jacob deGrom celebrated his 27th birthday by taking a shutout into the eighth inning. But he watched a slim 1-0 lead dissipate into the muggy air at Turner Field.

With two on and one out in the eighth, Gold Glover Juan Lagares misread Jace Peterson's liner to centerfield, charging at the ball before watching it sail over his glove.

Peterson's two-run double off lefty reliever Sean Gilmartin gave the Braves a 2-1 lead.

It happened partly because of another mental mistake earlier in the inning. With one out and a runner on third, shortstop Wilmer Flores fielded Pedro Ciriaco's grounder.

But he took too much time looking Andrelton Simmons back to third base, allowing Ciriaco to leg out an infield hit.

That set the stage for Peterson's clutch hit.

The runs were charged to deGrom, who departed following Ciriaco's infield hit, which came on his 97th pitch. In 7 1/3 innings, deGrom (7-5) allowed two runs, further improving his chances of carving out a spot on the National League All-Star team.

But the Mets lineup managed only modest success against Matt Wisler, the Braves' top pitching prospect who held the Mets to one run in eight innings in his big-league debut.

To ward off what he called sluggishness, and preserve energy on a muggy 89-degree day, Collins cut batting practice short. It made little difference.

The Mets cobbled together a run in the sixth to take a 1-0 lead.

Ruben Tejada led off by doubling off the fence in left-center, then advanced to third on a Lucas Duda groundout.

Michael Cuddyer knocked in Tejada with a chopper that bounced high over the head of the third baseman Chris Johnson, who got burned for playing in on the grass.

It was the only run allowed by Wisler, the highly touted prospect acquired from the Padres in a blockbuster trade for closer Craig Kimbrel and outfielder Melvin Upton Jr.

Until the eighth, the only hint of trouble for deGrom came in the fourth inning, when Curtis Granderson dropped Johnson's routine fly ball in shallow rightfield for a two-base error.

Johnson reached third when deGrom bounced a pitch past catcher Kevin Plawecki. But deGrom bounced back to strike out A.J. Pierzynski.