ATLANTA — Brian McCann stood at second base, convinced he had just hit a game-winning homer.

His teammates gathered along the first-base line, ready to celebrate.

After 86 seconds, umpire crew chief Tim McClelland popped out of the Florida dugout, looked toward McCann and twirled his right index finger — the universal signal for a home run.

Upon further review, the Braves win.

McCann capped a stunning comeback with a replay-assisted homer that gave Atlanta a 7-6 victory over the Marlins on Sunday — the first time a game ended on a call using video.

Without it, McCann might have only gotten credit for a double and the game would have continued on. Instead, he was jumping into the arms of his teammates after the umps took a second look, taking advantage of a limited replay rule that went into effect two years earlier almost to the day — Aug. 28, 2008 — to make sure they got these sort of calls right.

“I heard it hit the back tin (wall), so I knew that wasn’t the sound of the pads,” McCann said. “I knew it was a homer. I was telling Tim McClelland, ‘I promise you it’s a homer, I heard it hit the back.”’

Pinch-hitter Matt Diaz tied the game with a two-run homer off Leo Nunez (4-3) after Brooks Conrad led off the ninth with a walk. Nunez retired the next two hitters, then McCann drove a 1-2 pitch toward the wall in right.

The ball bounced back onto the field, and the umpires initially ruled it was still in play. McCann stopped at second and began arguing that he should have more than a double.

The umpires conferred, then headed toward the tunnel alongside the Florida dugout to look at a replay that clearly showed the ball struck the top of the wall — right over McCann’s name on an auxiliary scoreboard — and went over. It ricocheted back onto the field off the wall in front of the seats.

“Yep, that was a home run,” said Florida manager Edwin Rodriguez, whose team took a devastating loss in its long-shot bid to get back in the playoff race. “It was a home run all the way.”

When McClelland signaled homer, McCann finished his triumphant jog around the bases, slamming down his helmet before he touched home and disappeared into a mob surrounding the plate.

“It was the worst celebration of all time,” McCann quipped. “I got lost in the moment.”

The NL East-leading Braves overcame a 6-1 deficit, scoring three runs in the eighth and three more in the ninth for a victory they will surely remember if they hold on for their first division title since 2005.

“There’s not a better feeling,” McCann said. “It makes it better being in a playoff race.”

Takashi Saito (2-3) pitched a scoreless ninth for the win, while Nunez’s eighth blown save in 37 chances ruined a strong outing by Florida starter Josh Johnson, who pitched three-hit ball over six innings and allowed only an unearned run.

The Braves won for the 23rd time in their final at-bat, which leads the majors. It wasn’t even their biggest comeback of the season — a seven-run ninth gave Atlanta a 10-9 victory over Cincinnati back in May — but this finish will be remembered right alongside Conrad’s walk-off grand slam, especially if this team goes on to make the playoffs.

“What team hits two homers in the ninth inning to win a ballgame? Hopefully, that means we’re a team of destiny,” Diaz said. “If this continues, we’ll either all have heart attacks or make the playoffs.”

The long ball finished off the Marlins, but it was shaky defense that made a game of it. Florida committed three errors and gave up three unearned runs.

Rodriguez was more perturbed at the relievers — especially Nunez.

“At some point, the bullpen has to step up,” the Florida manager said. “With a five-run lead, you have to pound the strike zone. We were doing fine. But the bullpen was unable to hold a five-run lead. That’s unacceptable.”

Atlanta starter Derek Lowe appeared headed for his fourth straight loss, lasting only three innings. He got himself in trouble right away, giving up a three-run homer to Hanley Ramirez in the first.

Ramirez came out of the game two innings later after a slide into second base. He bent over and poked at his chest, then headed to the dugout with what the team described as lightheadedness.

Lowe surrendered six hits and walked three before leaving with his team trailing 5-1. Bobby Cox wasn’t around at the end, either — the Braves manager was ejected in the sixth after third-base umpire Mike Everitt ruled that Eric Hinske went around for strike three on an attempted check swing.

The Braves sure liked what the umpires ruled in the ninth, however.

Florida had no complaints.

“They got it right,” Dan Uggla said. “He hit a home run, and he deserved it.”

Right fielder Mike Stanton had the best look at it.

“It disappeared for a minute,” he said. “There was like a little rail, and it was behind it. Oh yeah, there was no doubt” it was gone.

Atlanta’s only run off Johnson came in the first after Omar Infante reached on a throwing error by second baseman Uggla, who made a nifty scoop up the middle, then bounced the throw to first. With two outs, McCann walked and Hinske came through with a run-scoring single.

Hinske, filling in at first for Derrek Lee, sparked the comeback with an RBI double in the eighth that made it 6-2 and left runners at second and third. Clay Hensley fanned Alex Gonzalez and should have escaped with no further damage, but first baseman Gaby Sanchez couldn’t come up with a low throw from Wes Helms after a grounder to third.

The ball skidded into the Atlanta dugout, the error allowing two runs to score.

NOTES: Lee didn’t play after coming out with a strained side muscle on Saturday night. He said it’s not a major problem and he hopes to be back in the lineup Monday. ... Cox extended his record for ejections with the 157th of his career and fourth of the season.