ATLANTA -- Ben Sheets loved being back in the majors so much that he broke normal custom for starting pitchers and watched the last three innings from Atlanta's hot dugout instead of the clubhouse.
"I like to do that and I've had very good feedback on it," he said. "You work so hard to get a victory. I ain't going to leave them out there. They're battling for me."
Freddie Freeman hit a three-run homer in a six-run fifth inning, and Sheets (1-0) allowed two hits and one walk with five strikeouts in his first start since July 19, 2010.
"I didn't know what to expect," Freeman said of his new teammate. "It didn't look like he took two years off."
The Mets have lost four straight and seven of 10. Atlanta improved to a season-high 10 games over .500.
Johan Santana (6-6) gave up eight hits, six runs, two walks and struck out three in five innings.
The Braves had placed just two runners in scoring position before Matt Diaz, who began the game with a .514 in 35 career at-bats against Santana, doubled to lead off the fifth.
After Paul Janish walked on a slider that appeared to cross the outside part of the plate for a strikeout, Michael Bourn hit a one-out, opposite-field RBI double down the line in left to score Diaz from second and make it 1-0.
Mets pitching coach Dan Warthen was ejected during a mound visit following Bourn's hit. When plate umpire C.B. Bucknor reached the mound, Warthen began arguing with him, apparently because Bucknor called Santana's fastball outside on the pitch that preceded Bourn's double.
"The Janish pitch -- that was a strike," New York catcher Josh Thole said. "I'm certain. And then the backdoor sinker to Bourn -- it was an outstanding pitch, and you ball that. Again, it changed the course of the game."
New York manager Terry Collins, who was ejected the day before, came on the field and spoke with crew chief Dale Scott near the third-base line, but walked back to dugout without further argument.
Martin Prado followed with a sacrifice fly RBI to score Janish, and Bourn crossed the plate from third on Jason Heyward's RBI single. After Chipper Jones singled, Freeman hit his 12th homer to give the Braves a 6-0 lead.
Kris Medlen replaced Sheets and gave up Andres Torres' RBI single to make it 6-1 in the seventh. Eric O'Flaherty got the third out of the eighth, and Anthony Varvaro pitched a scoreless ninth for Atlanta.
Sheets, unsigned after he missed all of 2011 following elbow ligament replacement surgery, escaped a jam in the third with runners on second and third when David Wright flew out to deep right.
Sheets threw 88 pitches, 57 for strikes. In his previous start two years ago, he lost 2-1 to Boston while pitching for Oakland.
Making his 242nd career start, Sheets improved to 91-92 and lowered his ERA to 3.77. Against the Mets, Sheets improved to 5-2 with a 4.05 ERA. The Braves purchased the former Milwaukee ace's contract from Double-A Mississippi before the game.
"He mixed his pitches well, and his command was outstanding," Atlanta manager Fredi Gonzalez said. "A little better than I thought it would be the first time out. He gave us a hell of an opportunity to win the ball game."
Santana hadn't pitched since twisting his right ankle while covering first base in an 8-7 loss to the Chicago Cubs on July 6.
Since throwing the Mets' first no-hitter on June 1 against St. Louis, Santana dropped to 3-4 with a 5.45 ERA in his last seven starts. He has given up 11 homers over that span.
Santana, who hasn't gotten a win against the Braves since Sept. 2, 2010, had the shortest start of his career, 1 1/3 innings, in a 9-3 loss at Turner Field on April 17.
"We felt that we threw good pitches and didn't get the call," he said. "It's tough when you have a game like this and one pitch could be the difference in the game. I didn't question anything, and it's too bad that a couple of pitches changed the whole ballgame."
The Braves haven't had a longer winning streak since they took 9 straight from May 26-June 3, 2010. ... Santana threw 95 pitches, 56 for strikes. It was the third time in seven starts that he has allowed at least six runs. ... Mets RF Lucas Duda will have his left hamstring examined by a doctor in New York on Monday. He was held out of the lineup for the second straight game. ... Janish, who was acquired in a Saturday trade with Cincinnati, played in the majors for the first time this season. The 29-year-old spent the last 3½ months at Triple-A Louisville. ... Prado made his first start at 2B since 2009. ... Gonzalez said RHP Randall Delgado will be recalled Saturday to start one of the Braves' doubleheader games at Washington. Delgado was optioned to Triple-A Gwinnett to make room on the roster for Sheets. ... Atlanta placed SS Jack Wilson on the DL to make room for Janish.