For three-plus quarters during Sunday’s Super Bowl LIV, Patrick Mahomes looked mortal, uncharacteristically missing on throws he usually completes. As the fourth quarter began, and the Chiefs drove to the 23-yard line of the San Francisco 49ers, their quarterback was picked off by Tarvarius Moore — Mahomes’s second interception of the day, just the fourth time in his career that he had thrown two or more INTs in a game. The Kansas City offense found itself in a familiar position: down two scores for the third-straight game in the playoffs. Yet compared to the previous games, things appeared slightly more desperate. After the interception, the Chiefs’ win probability stood at a meager 4 percent.
But then the 49ers’ offense — one purpose-built to grind out wins on the ground — sputtered. It could advance just 17 yards on five plays and a penalty before being forced to punt. On the next three K.C. drives, the vaunted San Francisco defense collapsed, allowing back-to-back-to-back touchdowns in a span of just over five minutes. For the second time in as many Super Bowl appearances, Kyle Shanahan’s team lost a game in which win probability models estimated that it should have won at least 95 times out of 100.
The decisive edge, as is often the case, could be found in the passing game. Despite struggling for most of the game, Mahomes finished with a QBR of 61.6 — substantially higher than Jimmy Garoppolo’s 40.6 — and the Chiefs passed 19 out of 29 offensive plays in the fourth quarter while mounting their comeback. San Francisco won the ground battle, averaging 6.4 yards per attempt and gaining more total rushing yards, but was unable to close out the game after establishing the run. The 49ers attempted just five run plays in their scoreless fourth quarter as they watched their lead evaporate.
Kansas City made ample use of play-action, running fakes 19 times to the Niners 15, including seven times in the pivotal fourth quarter for 56 yards and a touchdown. The Chiefs also benefited from two aggressive — and analytically correct — fourth-down play calls that set up two first-half scores.
San Francisco ultimately didn’t have enough answers for Mahomes. The Niners’ pressure forced him outside the pocket nine times, but despite scoring a sack, flushing Mahomes was mostly fruitless. Mahomes’s QBR was 68.2 when he played out of structure compared with 57.7 (including two interceptions) while in the pocket. Defensively, the Niners played primarily zone coverage against the Chiefs, and they weren’t particularly successful with it, allowing a QBR of 63.9. And while the 49ers had better success while in man — holding Mahomes to a QBR of 23.2 — they did so on just 15 dropbacks.
When Damien Williams ran unimpeded along the left sideline for the Chiefs’ final score, extending their lead to 31-20, he put an exclamation point on a win that was as indicative of the importance of passing offense as it was reminder of the unreliability of defense. The more balanced team lost because balance isn’t what wins in the NFL. The Chiefs are Super Bowl champions because they eschewed balance — and put the game in the hands of their quarterback when it mattered most.
CORRECTION (Feb. 3, 2020, 2:30 p.m.): A previous version of this article misspelled the name of the Kansas City running back who scored the game’s final touchdown. It is Damien Williams, not Damian.