4. Secondary thwarts Mahomes
The Niners led the NFL in pass defense, allowing 169.2 yards per game, double-digits better than any other team. That is a combination of an overall solid unit but also a tribute to the secondary. Getting Kwon Alexander back in the NFL Championship for the linebacker corps ratchets the defense up many levels. When he was out, SF allowed 100 yards more per game. He’s back and so is the defense’s mojo.