ATLANTA -- Yoenis Cespedes was hitless in the series opener against the Atlanta Braves, but the center fielder earned the MVP chants from New York Mets fans on Friday night.

Cespedes was 3-for-5 with three RBIs, and his mammoth two-run homer in the ninth inning capped a 5-1 victory that gave the Mets an 8 1/2-game lead in the National League East with 21 games to play.

"I think he's enjoying this as much as everyone else is," Mets manager Terry Collins said. "He's caught up in it. He came over and he's in a pennant race. ... I think it's catchy. We're seeing everything we've ever heard or read about a guy."

Cespedes, who has 33 homers and 100 RBIs overall, has homered in seven of his past 10 games and has 15 home runs and 39 RBIs in 38 games since being acquired by the Mets from the Boston Red Sox.

"He's just a great hitter," Collins said of his center fielder. "He uses his first at-bat to gauge what he's got to do. ... This is a new league. ... He sees what guys are doing and after that he's dangerous. ... He's got power to all parts of the park."

Cespedes' blast in the ninth, which traveled to the back of the lower seats in left field, came on 3-0 fastball from right-hander Arodys Vizcaino, who had walked right fielder Curtis Granderson to start the inning.

Granderson scored three times, and second baseman Daniel Murphy and left fielder Michael Conforto each had two hits. Conforto was also robbed of a hit on a catch by center fielder Michael Bourn.

The Mets picked up a game in the standings when Washington lost 2-1 at Miami.

"I'll be happy when we're up by 8 1/2 games with eight games to play," said Collins, taking nothing for granted.

Rookie left-hander Steven Matz improved to 3-0 while lowering his ERA to 1.88, and the Mets (80-61) took advantage of blunders by the Braves (56-86) to score on a balk and a passed ball.

Braves rookie right-hander Matt Wisler, who lost his fifth straight to fall to 5-7, balked in a run in the fifth inning, and a passed ball by catcher Christian Bethancourt gave the Mets another gift run in the eighth.

Matz, who developed a blister in his previous start, was pulled for a pinch hitter after five innings and 89 pitches. He gave up six hits and two walks as the Braves stranded seven runners against him.

Matz's only blemish was a home run by rookie second baseman Daniel Castro, who connected for the first time in his 18th major league game.

Wisler wasn't as sharp as he had been when he beat the Mets 2-1 in his major league debut on June 19, but it was his best outing since late July.

He gave up seven hits and two runs in six innings, throwing 63 strikes in 102 pitches. He struck out six and walked three (two intentionally).

"Wisler was good," Braves manager Fredi Gonzalez said. "I haven't seen the tape, but I'm not sure he balked. It was probably borderline."

The Mets' run in the eighth was set up when Michael Cuddyer, playing for the first time since Sept. 2, reached on a two-out infield single as a pinch hitter. Shortstop Ruben Tejada had a single before the passed ball.

The Mets went up 1-0 in the third as Granderson drew a leadoff walk and Cespedes followed with a double to right-center field.

The Braves loaded the bases in the fourth on two singles and a two-out walk, but Wisler was up next and Matz got him to ground out.

The Mets made it 2-0 in the fifth thanks to a balk by Wisler, who was called for not pausing in the stretch before making a pitch with Granderson on third after a leadoff single.

The Braves, though, cut the Mets' lead in half in the bottom of the inning as Castro lined a 2-2 sinker into the left-field seats.

"I wasn't trying to hit a home run," said Castro, who also made a stunning defensive play, through an interpreter. "I was down in the count and just trying to make contact."

NOTES: Mets pitching coach Dan Warthen returned to the team Friday without restrictions after missing Thursday's game and spending the night in an Atlanta hospital while being checked for an accelerated heartbeat. The issue corrected itself, the Mets said. ... Mets RHP Hansel Robles, who has made 48 relief appearances, is not with the team because of a death in his family. ... The Mets and Braves wore caps of New York City first responders during batting practice in recognition of the 14th anniversary of 9/11. ... All major-league game caps Friday included an American flag on the side. ... Braves CF Cameron Maybin was out of the lineup for the sixth consecutive game because of a scratched cornea and isn't expected back before Sunday. ... Mets RHP Noah Syndergaard (8-6, 3.31 ERA) will start Saturday against Braves RHP Williams Perez (5-6, 5.42).