Kurtenbach: January football is different. No team knows that better than the 49ers

There are two immutable truths that govern the NFL playoffs — unwritten rules that cut through the noise of EPA models and talking-head bluster.

Truth No. 1: In January, more games are lost than won.

Truth No. 2: When the margins are tight, trust the sideline with the better head coach and the quarterback.

Often, these truths independently operate. But on a windy Sunday night in Philadelphia, they intertwined in the 49ers’ 23-19 win over the Eagles.

While Nick Sirianni and Jalen Hurts spent three hours treating the national audience to a masterclass in self-sabotage, Kyle Shanahan and Brock Purdy simply… existed. They handled business. They survived.

And now, after a victory that felt more like an escape than a conquest, the 49ers are advancing.

Sometimes, the smartest strategy in football is to just get out of the way and let the other guys implode.

And this game was decided the moment the Eagles chose to fight themselves rather than their banged-up, bruised, but not-yet-beaten opponent.

Let’s start with Sirianni, the sideline mascot masquerading as a tactician. He doesn’t call the offense. He doesn’t call the defense. His primary job description appears to be “Chief Vibes Officer,” and on Sunday, the vibes in Philly were radioactive.

In the second quarter, with his team in control of the game, Sirianni sprinted down the sideline — not to make a schematic adjustment or point out a coverage flaw — but to publicly berate mercurial wide receiver A.J. Brown after a third-down drop. If a coach pulled that stunt at any level that wasn’t the NFL, it would be an instant viral “teaching moment” on how *not* to lead.

The result of this bizarre tirade? Shockingly, Brown didn’t suddenly discover the secrets of “Inner Excellence.” He dropped more passes. The Eagles’ offense, which desperately needs Brown to be elite to mask their schematic limitations — a polite way of saying “to cover for a struggling quarterback” —sputtered in concert.

Contrast that with Shanahan. The 49ers were starting strangers at key positions. George Kittle’s Achilles had popped, a devastating blow to the soul of the roster. The offensive line was leaking oil. And while Shanahan made questionable calls — every offensive play-caller does — he never panicked. And he certainly never made the moment about him.

He tweaked, adjusted, and maintained the game plan — because it was good enough.

Then there is the matter of the quarterbacks.

Brock Purdy was far from perfect on Sunday. He threw two indefensible picks. He missed other throws, too. He seemingly forgot where the sideline was at the end of the first half. But when the game tightened, Purdy stood in the pocket, took the hits, and delivered. He played with the cold demeanor of a guy who knows that the moment is only as big as you want it to be.

Jalen Hurts, meanwhile, played as if he wanted to be anywhere but that field.

There is no other way to frame it: Hurts played scared. Faced with pressure, he didn’t step up; he bailed. He turned clean pockets into scrambles and scrambles into throwaways. And then came the sequence that would define his postseason failure.

With the season on the line — fourth-and-11, less than a minute to play, trailing by four — Hurts and the Eagles burned a timeout.

It was a fatal, inexcusable error that was obvious the moment it happened. That timeout was their lifeline, their only chance to get the ball back if the play failed. By burning it, they turned a long fourth-down conversion into a binary proposition: Do or die.

And after heading to the sideline to draw up the perfect play to save the season, what did the Eagles’ brain trust — Hurts, Sirianni, and soon-to-be-fired offensive coordinator Kevin Patullo — return with?

Four verts.

That’s it. That’s the “break glass in case of emergency” play.

Again, Pop Warner stuff.

The Niners were thrilled. They didn’t know it was coming, but in their state, they were always going to show a simple coverage — quarters.

They gave Hurts an easy read, provided he was willing to stand and deliver. They didn’t think he would. They were right.

Instead, he lofted a prayer into triple coverage. A ball that had no business being thrown.

Waiting for it was Eric Kendricks.

Let’s pause to appreciate the absurdity: Kendricks was signing the paperwork to join the 49ers’ 53-man roster this week. He was an emergency depth signing, a guy recently sitting on the couch, who suddenly found himself as the team’s fourth starting linebacker of the season for a playoff game.

Yes, Kendricks has been around the block. And yes, all those months away from the field meant his legs were fresh. He diagnosed the play, drifted back, and broke up the pass with the savvy only a crafty vet possesses.

The pass breakup was a nice narrative bow, but let’s be real: Hurts was outplayed by a linebacker who didn’t have a job until Tuesday on a downright embarrassing play call.

Yes, the 49ers won Sunday because the Eagles lost.

It sounds like a tautology, some sort of vague fortune-cookie wisdom. But it’s the truth.

Purdy now has four game-winning drives in the playoffs — tied for the most of anyone in the NFC field. Hurts might have a Super Bowl MVP trophy on his mantle, but he has never led a playoff game-winning drive in 10 playoff games.

Now, the hard road gets even harder for San Francisco.

The bracket resets, the Seahawks loom next.

So we return to Truth No. 2: Who do you trust?

Despite the roster attrition, who would you rather have than Purdy and Shanahan?

We will concede Sean McVay and Matthew Stafford in Los Angeles. How could you not pick them?

But Chicago’s duo of Ben Johnson and Caleb Williams? Please. A nice story, a fun ride, but are you really trusting that by-the-seat-of-their-pants operation in the crucible of the NFC Championship?

Seattle? I’ll bet on the head coach, the madman Mike Macdonald, and a defense that bludgeoned the Niners in Week 18. But then there’s Sam Darnold, who led the NFL in turnovers. Are you really going to trust him not to see ghosts when the lights get bright?

The 49ers have problems. They carry the scars of past failures. But they have the muscle memory from victories, too.

They have a coach who, for all his faults, schools the likes of Sirianni in his sleep. They have a quarterback who doesn’t need to be carried, despite what the head-in-the-sand national pundits think.

Sunday was a reminder that in the NFL playoffs, you don’t need to be perfect. You just need to be the adults in the room.

The Eagles were children. The 49ers were the adults.

They survived. They advanced. And right now, that’s the only truth that matters.