The Chiefs won that game with Mahomes and a great defense. 
SF was 3 of 12 on third down. That's bad. They averaged 45% this year. 
McCaffrey had 80 yards on 22 carries (3.6) and only 4 first downs. He 'only' had 6 carries for more than 5 yards and his long was 11. He's usually good for a 15 - 20 yard burst or two every game. In the 2nd half, prior to OT, he had 7 carries for 22 yards. In OT he did better....25 on 6 carries. Over all, 10 of his 22 carries gained 3 yards or less. Add to that his lost fumble and not a very CMC day. 
Shanahan? The Chiefs D? A combination of both? 
All I know is I'm happy as hell. 
The McVay vs Shanahan box score goes like this.
Head to head. 
Shanahan 10, McVay 4.....PS McVay 1-0
Overall. 
Shanahan 64-51, 8-4 in PS, 2-2 in CCG, 0-2 in SB
McVay 70-45, 7-4 in PS, 2-0 in CCG, 1-1 in SB
I'll take our guy!