"I'm more frustrated for giving up somebody else's runs and making it close," Kimbrel said.
Santana (1-0) was sharp from the start, throwing 28 strikes in his first 29 pitches. He finished with six strikeouts and no walks. He said he didn't expect to have such strong command.
"Honestly, no. In the bullpen I was all over the place," Santana said. "I just stepped over the line and focused and threw strikes."
Santana signed a $14.1 million, one-year contract with Atlanta after the Braves lost starters Kris Medlen and Brandon Beachy to season-ending elbow injuries last month. He pitched like he belongs near the top of the rotation as he threw only 88 pitches, 65 for strikes.
Zack Wheeler (0-2) allowed four runs on eight hits in five innings for the Mets.
Heyward took a 0-for-22 slump into the game and was hitting only .107, with three hits in 28 at-bats. He doubled his hits total with the homer and two singles in his first three at-bats.
Heyward led off the first inning with an 11-pitch at-bat against Wheeler before pulling a 3-2 fastball over the wall in right-center for his second homer.
"It's a tough way to start the game, going that deep into the count and him hitting a home run, but it was a good at-bat for him," Wheeler said. "He just came out on top on that one."
The Braves added three runs off Wheeler in the fifth. Evan Gattis doubled and scored on Heyward's single to right field. Santana, who slapped a single to right for his fifth career hit, and Heyward scored on Freddie Freeman's single.
Each team had defensive highlights early in the game.
In the first inning, Lagares raced back to make a leaping catch of Freeman's drive at the wall, his cleat leaving a rip in the cushion.
Shortstop Andrelton Simmons showed his Gold Glove form in the second. The shortstop went to his right to field a grounder by d'Arnaud before slipping, hopping up to one knee and throwing out d'Arnaud at first base, with Freeman stretching for the throw.
An excited Santana pumped his fist, shouted and pointed at Simmons.
Santana celebrated with another fist-pump after Heyward, sprinting toward the right-center gap, ended the sixth by catching Wright's drive before falling on the warning track.
Braves LHP Luis Avilan, who left Tuesday night's game with a hamstring cramp, had no problems throwing in the bullpen before Wednesday's game and said he'll be careful to remain hydrated in cooler weather. ... CF Jordan Schafer was 0-for-3 in his first start of the season. Manager Fredi Gonzalez said B.J. Upton, hitting .138, will be back in the lineup on Thursday. ... Braves LHP Mike Minor (sore shoulder) and RHP Gavin Floyd (elbow surgery) are scheduled for their next rehab appearances on Sunday. ... RHP Pedro Beato was optioned to Triple-A Gwinnett to clear a roster spot for Santana. ... Braves RHP David Hale will face Mets RHP Jenrry Mejia in the final game of the series on Thursday night.
Copyright by STATS LLC and The Associated Press
ATLANTA, GA - APRIL 09: Centerfielder Juan Lagares #12 of the New York Mets makes a catch against the wall during...
19,608 (39.7% full) - % is based on regular season capacity
65 degrees, clear
Home Plate - Mark Ripperger, First Base - Gary Cederstrom, Second Base - Kerwin Danley, Third Base - Lance Barksdale
Freddie Freeman was 2-4 with 2 RBI vs the Mets on Wednesday. Freeman has 37 RBI vs the Mets since the start of the 2012 season, by far the most in the majors in that span.
Freeman is a .309 career hitter against the Mets. Coincidentally, fellow-Mets killer Chipper Jones finished his career with a .309 batting average against them.
Ervin Santana is the 3rd pitcher with at least 8 scoreless innings in his first game with the Braves since the team moved to Atlanta in 1966.
The others to do this were Greg Maddux in 1993 and Derek Lowe in 2009.
From Elias: Ervin Santana threw 20 consecutive strikes to start the game. He's the only player in the past 15 seasons to start a game with 20 consecutive strikes.
New York Mets batters have hit .197 in at-bats to end in a slider from a righty since the start of last season, fourth worst in the majors. Ervin Santana has thrown his slider 38 percent of the time over that span, second most among qualified pitchers.