ATLANTA -- If the beginning was stunning and mystifying in its inefficiency, the end was no less striking in its magnificence.

The 49ers all afternoon had played from behind, trailing Atlanta from the opening minutes, the deficit growing as high 17 points. Their offense couldn't get anything, and, shockingly, their defense was giving up everything.

So when the 49ers finally fought back to take a lead midway through the fourth quarter Sunday, putting the Super Bowl on the horizon, a simple question hung in the air:

Can this defense, torched early and so often during this NFC Championship game, summon the grit and skill to send the Falcons into the offseason?

The answer was emphatic. San Francisco is going to its sixth Super Bowl because its defense, its steadiest unit the past two seasons, recovered from a dreadful first half to secure and deliver a 28-24 victory over the Falcons.

The 49ers defense made two plays in the red zone over the final 78 seconds to allow their fans to exhale and bury the pesky and talented Falcons before 70,863 roaring fans at the Georgia Dome.

"I was telling the defense throughout the game that this game is going to come through us, and that we're going to have to win this," safety Dashon Goldson said. "We started slow, but it was going to have to come through us."

After Frank Gore's 9-yard touchdown put the 49ers up with 8:23 remaining, Atlanta took possession 80 yards away from the end zone. The Falcons gained 64 yards, 22 of which came on a challenged pass catch, to reach the San Francisco 16 with 2:23 left.

They gained 1 yard on a run and 5 on a pass, with linebacker Patrick Willis making both tackles. But the Falcons went no further than the 10, as Ahmad Brooks batted down a Matt Ryan pass on third down and NaVorro Bowman broke up a fourth-down pass to lock things up.

"It was just good team defense," Goldson said. "We started seeing formations and communicating amongst each other. When we do that, when we're on the same page, it's hard to beat us."

This was sweet redemption for the members of the defense after a forgettable first half, when they too often watched helplessly as Ryan fired perfect passes over and past them. Rarely was he under pressure, and his receivers, particularly wideout Julio Jones, treated San Francisco's defense like padded scarecrows.

It was ugly and it looked grim for the 49ers defense. The rock of this team was, on the scoreboard and by the eye test, on the brink of despair.

And then it recovered spectacularly to shut out the Falcons after halftime.

"Over the last two years, our short history of being together, we never blink," safety Donte Whitner said. "When things go bad out there -- we give up a touchdown or blow a coverage or miss a tackle -- we never blink because we know we can fix it. We know who we are. We know the capabilities of these guys in this locker room."

The unit responded to the urgings and scheming of defensive coordinator Vic Fangio, who made a few subtle coverage changes and found ways to put more pressure on Ryan.

Ryan's first half: 18 of 24, for 271 yards and three touchdowns. His second half: 12 of 18, for 125 yards, no touchdowns and two turnovers, a fumble and an interception.

"This is the defense you want to have, because no matter what kind of adversity there is, no matter what happens, we're going to step up to the task," Bowman said.

The 49ers had turned an unsightly first half into a display of gloriously imperfect, winning football.

"Things are not always going to be perfect," said Willis, who made a game-high 11 tackles. "People have their expectations, and we have expectations of ourselves. We want to go out there and, on every series, not give up anything. Or on every series, take it away. But you have to understand that without the ups, you don't have any downs. Without the good, you don't have any bad. What makes it that much more amazing is when you go through adversity and you're able to go out on top.

"It was tough. It was a fight. It was one of those games people will talk about."

People will talk about this game because it was highly entertaining, highly competitive, and the weaknesses of both teams were impossible to hide. The Niners couldn't cover the Atlanta receivers, none of them, and their pass rush was barely a rumor. And the Falcons, true to their history, could not finish.

People will talk about this game because both quarterbacks shined, because it decided the NFC representative for the Super Bowl and because, yes, San Francisco's defense, after a sorry first half, with its back to the end zone in the final minutes, went from suspect to respect.

"We knew it was going to come down to us getting a stop on defense," Whitner said. "And we went out there and got a stop."

Had to, if they were to continue pursuing the franchise's sixth Lombardi Trophy.

The defense that has been as good as any in the league the past two seasons gave up 477 yards, 396 through the air. It allowed 27 first downs and an average of 7.2 yards per play.

It did not, however, allow the Falcons to finish with an end zone celebration.

And being better at the end is one sign of a team with the heart of a champion.

Contact Monte Poole at mpoole@bayareanewsgroup.com Follow him at Twitter.com/1montepoole.