It is Shanahan's first trip back to the Super Bowl since the 2016-17 campaign when he served as the Atlanta Falcons offensive coordinator, and the Falcons infamously botched a 28-3 fourth-quarter lead to lose 34-28 to the New England Patriots.
Shanahan was asked by reporters Monday if he still thinks about losing Super Bowl LI.
"Not much at all anymore, to tell you the truth," Shanahan responded. "You do it every second in the days after; they were real tough. Losing the Super Bowl is extremely tough for everybody, especially when you have a 28-3 lead going into the fourth."
"But the way it came down on me personally, I didn't react to that the way people would expect because there were definitely parts of that Super Bowl I would love to have back and I was very hard on myself. But the whole narrative of 'if I just would have run it, we would have won,' I know that wasn't the case. I know what went into that game and all the stuff that happened, so that stuff didn't bother me. You've got to deal with that and listen to other people, but it was nice to be able to move on and move out here and just keep working. I'm glad I'm going to get the chance to go back."
It was a tough first two seasons in charge. San Francisco went 6-10 in 2017, then saw 2018 derailed when quarterback Jimmy Garoppolo's torn ACL headlined numerous injuries en route to a 4-12 record.
With Garoppolo back healthy and 2019 second overall pick Nick Bosa bolstering a dominant defensive unit, the Niners finally blossomed this season. San Francisco went 13-3 in the regular season and earned the NFC's top seed.
Shanahan has already made history by making his first Super Bowl as a head coach:
The 49ers will clash with the Kansas City Chiefs in Super Bowl LIV. Chiefs head coach Andy Reid knows what it feels like to lose a Super Bowl. He last made it this far as the Philadelphia Eagles head coach in 2004-05 and lost 24-21 to the New England Patriots.
Reid is the winningest head coach in league history without a Super Bowl or NFL Championship, per NFL Research.
One head coach will achieve redemption, while the other will be doubly heartbroken.
The Chiefs and Niners will kick off Super Bowl LIV on Feb. 2 at 6:30 p.m. ET from Miami's Hard Rock Stadium.