ATLANTA -- Matt Harvey described his pitching as "a work in progress" following his first win of the season.
With the Mets continuing their home-run spree, that was more than enough.
Granderson's sixth career grand slam was a line-drive shot he pulled into the right-field seats off Bud Norris (1-3) in the second inning. Granderson had three hits, including another homer off Norris in the fourth, giving him four on the season.
New York has 21 homers in its last seven games -- the most in a seven-game span in franchise history, according to the Elias Sports Bureau.
Granderson insisted he was "Not locked in at all."
"I'm just trying to go ahead and get pitches you can put a good swing on and I was able to do that on a few of the at-bats there," Granderson said.
Harvey (1-3) ended a streak of four straight losing decisions, including his first three starts this year. He needed 101 pitches to make it through five innings as he allowed two runs and seven hits and one walk.
"It felt like I was releasing the ball the way I should be," Harvey said. "There's more positives than negatives out of this game."
Harvey gave up a walk and two hits in the fifth but got out of the inning when center fielder Yoenis Cespedes threw out Nick Markakis at the plate. Markakis tried to score from second on A.J. Pierzynski's third single.
"I'm thrilled that we got a bunch of runs and I was able to kind of limit the damage there and help us get a win," Harvey said.
Jeurys Familia pitched the ninth for his fourth save.
The Braves have not hit a homer in their last 11 games, their longest drought since going 13 games without a homer in May 1983. Atlanta is last in the majors with only three homers and has no player with more than one.
The Mets have won six of eight. The Braves, who lost nine straight to open the season, have a new three-game losing streak.
The Braves matched the Mets' 10 hits, but they couldn't find enough key hits.
"We just haven't been able to get anybody on base and string anything together," Braves manager Fredi Gonzalez said.
Norris lasted only four innings and gave up five runs, four earned, on five hits and two walks.
The game was delayed by rain and lightning for 56 minutes in the eighth inning.
Home-plate umpire Jeff Kellogg left the game between the first and second innings after being hit by a foul tip. He walked off the field after being examined by Braves assistant trainer Jim Lovell. Alan Porter, who had been the first-base umpire, took over behind the plate on the three-man crew.
There was no immediate report on Kellogg's apparent injury.
Mets pitching coach Dan Warthen left the team following his mother's death. Bullpen coach Ricky Bones took Warthen's spot in the dugout and visited Harvey on the mound in the fifth inning.
Mets: Cespedes left the game after aggravating his bruised right leg while sliding into second with his seventh-inning double. He initially remained in the game. His exit was announced during the rain delay in the eighth.
Mets: LHP Steven Matz will put his unbeaten career road record on the line when he starts against the Braves on Saturday night. Matz is 3-0 with a 1.86 ERA in five career road starts, including a win at Atlanta on Sept. 11, 2015.
Braves: RHP Jhoulys Chacin will look for his first win of the season. Chacin has pitched well, with a 2.38 ERA in two starts, but he does not have a decision. Chacin is 1-2 with a 2.88 ERA in five career games against the Mets.
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