ATLANTA - Steven Matz, the brilliant rookie lefthander, looked rusty in his second start back from the disabled list. The Mets offense, a juggernaut since the trade deadline, failed to get a hit with runners in scoring position.

Neither seemed to matter for the Mets, who have turned winning into a matter of habit. After dispatching the free-falling Braves, 5-1, on Friday night, the Mets opened up an 8 1/2-game lead in the NL East over the Nationals.

Not since 2006 -- when the Mets ran away with the division -- have they enjoyed such a comfortable advantage. As the faltering Nationals took another kick to the teeth, losing, 2-1, in Miami, the Mets won their fifth straight.

Yoenis Cespedes continued his magical run with the Mets, knocking in three runs, including a mammoth two-run homer that provided breathing room in the ninth. In a season that began with the Tigers, he has hit 33 homers and knocked in 100 runs.

The Mets also scored on a pair of gifts, a fifth-inning balk by Braves starter Matt Wisler, and on an eighth-inning passed ball.

After Matz allowed just one run in five innings -- on a solo shot by Daniel Castro -- he handed a 2-1 lead to a bullpen that pieced together four shutout frames.

With the Mets clinging to a one-run lead, Erik Goeddel worked a clean sixth inning ahead of Addison Reed, who strengthened his lock on the seventh inning by striking out the side.

Setup man Tyler Clippard worked through trouble in the eighth ahead of closer Jeurys Familia, who pitched the ninth even though the Mets led by four runs.

The offensive outburst and a stellar night by the bullpen covered up for Matz, who in the fourth inning, pulled his glove to his mouth and let out a scream. He had just averted a crisis, one of several he was forced to navigate.

He walked off the mound, drenched in sweat, resigned to a night in which command evaded him.

Matz missed his spots with his fastball and displayed only flashes of consistency with his curveball, perhaps a sign of rust in just his second start following a two-month stay on the disabled list with a partially torn lat muscle in his left side.

Matz, 24, scattered six hits, the most in four big-league starts. He struck out just two, his fewest.Manager Terry Collins hoped that a return to routine might smooth out the bumps, especially after a blister on his pitching hand slowed him in his last outing.

"I think it will help, the fact that he's coming back on regular rest this time," Collins said. "[The] finger seems to be OK. We're hoping that he gets to that hundred pitch mark tonight and we're in the game."

Matz got the hook after 89 pitches.

But the Mets opened up a cushion despite going 0-for-9 with runners in scoring position.

Cespedes gave the Mets a 1-0 lead in the third when he ripped a double to the gap in right-center, allowing Curtis Granderson to score from first.

In the fifth, Wisler's balk allowed Granderson to score from third base. The Mets didn't score again until the eighth, when a passed ball by catcher Christian Bethancourt allowed pinch runner Eric Young Jr. to score.

Cespedes gave the Mets a four-run advantage in the ninth, squashing any realistic hopes of a comeback. His two-run shot was his seventh homer in his last 10 games.

Since joining the Mets at the trade deadline, Cespedes has hit 15 homers with 39 RBIs.