The teams will resume play with none out in the top of the ninth inning tonight at 6:10 p.m. The regularly scheduled game is set to start 7:15 p.m.
With rain starting to fall heavily, Gattis put Atlanta up 5-3 with a bases-loaded single off Greg Burke. The Mets tied it in a wet and wild bottom half, taking advantage of center fielder B.J. Upton's error on Daniel Murphy's RBI single and scoring on a wild pitch by Anthony Varvaro.
The game was suspended after a 75-minute delay.
Varvaro could be seen struggling to get a good grip on the ball throughout the inning, repeatedly rubbing his hand on his jersey and pants. Catcher Brian McCann even visited Varvaro to calm him down.
The tarp was brought out after Rick Ankiel struck out to end the eighth.
The Braves were trying for their seventh straight win — they swept two home series — but only a second win in seven road games. The Mets were swept by Cincinnati in a three-game series at Citi Field. They entered Friday's game 0-9 in games following a start by rookie star Matt Harvey.
New York led 3-2 behind the impressive pitching of Jeremy Hefner for six innings, but LaTroy Hawkins gave up a homer to Dan Uggla leading off the seventh to tie it. It was Uggla's fourth hit in 38 at-bats.
Hefner gave up a two-run homer to Freddie Freeman in the first then was sharp the rest of his outing, giving up three hits and two walks. He struck out seven. But Uggla's homer ensured he would remain winless in his nine starts.
Braves starter Kris Medlen allowed three runs and seven hits in six innings. He struck out nine, but yielded a homer leading off the fourth to John Buck that tied it 2-all.
Justin Upton was walked by Scott Rice with one out in the eighth and advanced to third on Freeman's single. Rice struck out McCann for the second out and was replaced by Greg Burke. Uggla walked to load the bases for Gattis.
The rookie with a made-for-Hollywood story came to the plate having hit three homers — two as a pinch-hitter — in his last six at-bats, including a grand slam on Wednesday. As a heavy rain started to fall, he worked the count to 1-2 before lining a single up the middle.
Struggling in the downpour, Varvaro walked Buck then struck out Ike Davis — his fourth strikeout of the night — and pinch-hitter Jordany Valdespin before Ruben Tejada singled.
Murphy hit a soft line drive to center field that hit off Upton's glove as he came in on it and Buck scored.
Tejada was able to race to third base when B.J. Upton struggled picking up the ball. Varvaro bounced the first pitch to Ankiel and it scooted to the left of catcher Buck allowing Tejada to score and tie it 5-all.
New York last scored more than four runs at home on April 24, a 7-3 win in 10 innings over the Dodgers.
NOTES: Braves RHP Brandon Beachy, who underwent elbow surgery in June 2012, made a rehabilitation start for Triple-A Gwinnett on Friday night. He allowed two runs and two hits in four innings, also walking three and striking out three. ... Mets RHP Jenrry Mejia (elbow inflammation) is set to have a rebab outing today for Class A St. Lucie. ... Braves manager Fredi Gonzalez said Gattis and McCann will split the catching and designated hitter duties for the two-game series in Toronto next week. Atlanta's third catcher, Gerald Laird, is lined up to be behind the plate against the Mets on Sunday for Julio Teheran's start. ... Braves 3B coach Brian Snitker stayed in Atlanta to see a back specialist. Carlos Tosca coached third. ... Mets 3B coach Tim Teufel was attending his daughter's high school graduation in Florida. Bench coach Bob Geren coached first and Tom Goodwin moved from first to third.