The San Francisco 49ers looked in a hopeless position at the half of the NFC Championship Game down 24-7 to a Detroit Lions team whose offense appeared unstoppable.

NFL locker rooms at halftime are such a frenzy that the head coach is ill-equipped to deliver an inspiring message to turn things around. 

However, 49ers head coach Kyle Shahanan did not need an inspiring message. All it took was a statement of facts to get the Niners to right the ship and pull off one of the most incredible comebacks in playoff history.

San Francisco roared back in a second half that will live in franchise folklore. The 49ers scored 27 unanswered points to claim a 34-31 victory and punch their ticket Super Bowl 58 and a rematch with the Kansas City Chiefs, whom the Niners lost to in Super Bowl 54.

The secret at the half, keeping it simple.

"We just pulled them up and said 'guys it's only 17 points,'" Shanahan told his postgame press conference. "'Been a lot of football games where we're down 17 points, we're starting with the ball, that's plenty of time to comeback, plenty of points to comeback but, regardless of any of that stuff, we're not going out like this, we've got to be a lot more aggressive in the second half in everything we do.'"

It was a straightforward message that resonated as the 49ers replicated the largest comeback in NFC Championship Game history, matching the 2012 San Francisco team that fought back from a 17-point deficit against the Atlanta Falcons.

A defense that struggled to stop anything the Lions did in the first half held them without a point in the second half until Jameson Williams caught a three-yard touchdown pass with under a minute left. The 49ers subsequently recovered the onside kick.

San Francisco stopped the Lions twice on fourth down as Detroit head coach Dan Campbell's aggressiveness came back to bite him, while the 49ers also forced a key fumble from Jahmyr Gibbs after they had trimmed the deficit to one score.

"I thought we switched up a little bit more, tightened up on some things with some pressures, some man coverage," added Shanahan. "Guys didn't want today to be the last day and we put ourselves in a hole but they played like it in the second half. We were able to get the ball to bounce the right way and we made up for what we did in the first half.

San Francisco defensive coordinator Steve Wilks was a man under severe scrutiny after the first-half performance, but he never had any doubt things would turn around.

"Just character, man," Wilks told Matt Maiocco of NBC Sports Bay Area. "The men in that locker room, I knew for a fact that we were going to win that football game. 

"It wasn't really a lot of yelling and screaming. We just talked about the things that we had to correct and everybody had to do their job."

The 49ers did their job in remarkable fashion in the second half and, while the comeback featured several chaotic plays, San Francisco displayed a clear composure and belief as they surged their way back to one of the most memorable postseason victories in franchise history.

They still have one more substantial hurdle to clear in the form of Patrick Mahomes and the Chiefs but, if the 49ers do end the year lifting the Lombardi Trophy, it will owe a great deal to the calm messaging of the coaching staff when things looked their bleakest.

49ers favored to exact revenge in Super Bowl 58

They have unfinished business.