SANTA CLARA -- As the Falcons’ offensive coordinator three years ago, Kyle Shanahan came away from his first trip to a Super Bowl having learned a few lessons. The biggest one was not that he didn’t call a run play on that fateful second-and-11 situation in the fourth quarter against the Patriots.

Shanahan will be making his second Super Bowl appearance in less than two weeks and his previous experience has shaped the way he approaches a game forever. While there are always plays that he would like to have back, it’s a bigger lesson that left an imprint on the 49ers play caller.

“Losing a Super Bowl is extremely tough for everybody especially when you lose when you had a 28-3 lead going into the fourth,” Shanahan said. “The learning moments are — never feel good.

“I mean that’s why I promise you when we we're way up in the fourth quarter on Green Bay and stuff, I know what 28 minus three is. And I know a 25-point lead in the fourth quarter isn’t enough.”

While 28-3 is the score everyone remembers, the Falcons actually led 28-9 entering the fourth quarter of Super Bowl LI.

That mentality hits home for Shanahan during every game, and obviously reoccurred in the 49ers' 37-20 win over the Packers in the NFC Championship Game.

“So when we have a 14-point lead with eight minutes to go against Green Bay, I can promise you that I feel, from experience, like the game is tied and that we don’t have a two-score lead.”

Shanahan will forever feel like a team has the ability to mount a comeback but he knows that one play call towards the end of the game was not the reason Atlanta lost. In the first half of Super Bowl LI, Devonta Freeman and Tevin Coleman ran the ball nine times for 86 yards, averaging 9.6 yards per carry.

In the second half, the Patriots shut down the run game and the two backs ran the ball nine times for 18 yards, averaging only two yards per carry.

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Shanahan admits he will never call a perfect game, because that is an impossible feat, but he vows to never take his foot off the gas.

“I think that’s the stuff that helps you because I think sometimes people can tend to relax,” Shanahan said. "That’s something that I, I won’t say that I ever relaxed in that Super Bowl especially with Tom Brady having the ball. But that’s something that keeps you humble every single moment until the game is over.”

Programming note: NBC Sports Bay Area feeds your hunger for 49ers Super Bowl coverage with special editions of “49ers Central” all week (5:30 p.m. Monday and Wednesday; 8:00 p.m. Tuesday and Thursday; 6:00 p.m. Friday).