A look back at Super Bowl 54: Where it all went wrong for Shanahan and the 49ers

The San Francisco 49ers were in complete command through three quarters of Super Bowl 54. Their run game was dominant, their offensive line was pulling well and picking up blitzes, and their defense was stellar. It was just the second time all season that a defense was able to hold the Kansas City offense to 10 points or less through three quarters of play (Colts, week 5).

The 49ers' game plan defensively was to take away the big yardage plays from Mahomes. Let the Chiefs offense move in small increments down the field and force Mahomes to make the intermediate throws over and over until he got bored. They did this through a lot of zone coverages. Cover 4 "Quarters", Cover 3 "Cloud", schemes designed to take away the deep portions of the field using cornerbacks and safeties, while the linebackers blanketed the first down line, begging Mahomes to continuously throw into the flat or underneath.

All was going to plan for San Francisco until approximately midway through the fourth quarter. Allow me to paint the picture.

The Chiefs have the ball at their own 35-yard line. It's 3rd & 15 with 7:13 left in the fourth quarter. The 49ers are up 20-10, in prime position to force a punt and wind the clock using their run game. Mahomes snaps the ball, drops back, and delivers a 44-yard heave to a wide-open Tyreek Hill? Huh? To this point, Kansas City's offense had had only one play of 20+ yards! What happened?

Here's what happened. For some reason, defensive coordinator Robert Salah dialed up a cover 1 zone scheme, overloading the line to gain with linebackers and cornerbacks. The 49ers only rushed four guys, giving Tyreek enough time to develop his route downfield and spin safety Jimmy Ward around. It was as if Salah forgot who he was playing against after three quiet offensive quarters. Nonetheless, Mahomes made the Niners pay for this miscue, and the Chiefs entered the outskirts of the red zone with six and a half minutes left to play.

A few plays later, the Chiefs faced a 3rd and 10 from the 21-yard line. They broke the huddle in a 3x2, empty-set backfield, also referred to as 01 personnel. The 49ers were in cover 1 press-man with a five-man front, another alarming play call by Salah. Sure enough, Mahomes targeted Travis Kelce in the end zone, who drew a pass-interference penalty, setting up the Chiefs with a 1st and goal from the 1-yard line. Kelce would catch a touchdown pass a play later, narrowing the 49ers lead to just three points.

The 49ers would get the ball back and only manage to drain the clock to around the 5-minute mark before punting it back to Kansas City. On 2nd and 7 with 3:15 left and the Chiefs just over midfield, Salah and the 49ers' defense ran another questionable coverage.

The Chiefs came out in an 11-personnel package (1 RB, 1 TE, 3 WR). The 49ers showed a basic cover 2-man look pre-snap. Mahomes took the snap and cornerback K'Waun Williams blitzed from the slot, forcing safety Jaquiski Tartt to have to slide down to pick up Williams' man (WR Demarcus Robinson). Safety Jimmy Ward was then the lone man responsible for over-the-top, middle-of-the-field coverage, with all of Kansas City's receivers seeing man-to-man. Sammy Watkins burned Richard Sherman on the outside to get the Chiefs to the 49ers' 10-yard line. 3 plays later, Damien Williams would score on a pass to the flat, giving the Chiefs a 24-20 lead. The Chiefs would go on to win Super Bowl 54 by the score of 31-20.

All game, the 49ers had the Chiefs right where they wanted them. The defense was not giving Mahomes these man-press, single high looks until the final few drives. It didn't make sense then, and it still doesn't make sense now. Of course, Sunday's game features two completely different types of teams than what we saw in Super Bowl 54, however, the message on the 49ers' end still holds true. Stick to what is working. Don't get cute in the fourth quarter if you don't have to. Enter the game with a strong game plan, make adjustments as needed throughout, and ride into the sunset with the Lombardi trophy.