The Chiefs were exactly who we thought they were — and won Super Bowl LIV

Welcome to my analytical breakdown of the Kansas City Chiefs’ Super Bowl victory — words that would have sounded completely insane as recently as a few years ago.

But here we are.

As I sat down to write this article, I was a bit perplexed. Nothing occurred in the game that I hadn’t already touched upon in previous articles. Third-and-very-longs have been no problem for the Chiefs. Andy Reid needed to be more aggressive on fourth downs. Patrick Mahomes has been quite literally unstoppable when he absolutely has to score and Sammy Watkins has been a huge help this postseason. Finally, the Chiefs’ improved defense has made a huge difference.

That’s when it hit me: to win this game, the Chiefs didn’t need anything new to happen.

They just needed to be exactly the team we’ve said they are: an elite offense fueled by an exceptional quarterback who is unafraid to take risks, joined with a great supporting cast and a decent defense — plus a coach who is willing to be a bit more aggressive on fourth downs during the postseason.

That was all that was required.

So let’s highlight each trend we discussed earlier in the season that showed up big on the biggest stage.

Fourth down aggressiveness

After losing to the Tennessee Titans in Week 10, I wrote about how Andy Reid must be more aggressive on fourth downs. Many coaches view a made field goal as a success, ignoring the opportunity cost that comes with them — namely, potentially leaving four additional points on the field.

But against San Francisco on Sunday, the Chiefs were faced with two fourth-down decisions in the second quarter that eventually led to points. From an analytics standpoint, the first one — a fourth-and-1 from the 49ers’ 5-yard line — was a no-brainer. But in that situation, many coaches would be — and have been — too timid to pull the trigger. The decision to go for it substantially improved the Chiefs’ win probability — even before we knew they’d convert it.

The other was a fourth-and-1 at the San Francisco 19-yard line. By the numbers (especially with the Chiefs leading 7-3), this decision was also clear — but it was still nice to see Reid be aggressive. Unfortunately, the next few plays didn’t go well. The Chiefs ended up facing a fourth-and-long, ending up with three points on the drive anyway.

Third-and-very longs

After the Chiefs dismantled the Chicago Bears in December, I wrote about how the team had been converting third-and-very-longs at a ridiculous rate — and that this was largely driven by Mahomes’ average depth of target in these situations.

This held true again on Sunday. The Chiefs had only one third down of 15 yards or longer — and it was a pivotal moment.

Mahomes’ throw to Tyreek Hill traveled 43 air yards (measured vertically from the line of scrimmage to the point of the catch), which made it the third-deepest pass of the game — and the only one them that was completed. (The other two were the Mahomes’ final heave on the last play of the game — that no one was meant to catch — and Jimmy Garoppolo’s desperation throw with a minute left).

After including the Super Bowl, how does Mahomes compare to the rest of the league on third down with at least 15 yards to go?

Basically, Mahomes breaks the chart.

Improbable comebacks

Just three weeks ago — after the insane comeback against the Houston Texans in the Divisional round — I showed you that when their team has a very small chance of winning a game, no quarterback has been better than Mahomes.

This couldn’t have been clearer against the 49ers. The Chiefs were behind by 10 points when they got the ball with less than nine minutes left. At that point, most win-probability models gave the Chiefs less than a 10% chance to win — some as low as 5%.

But then Mahomes completed that deep bomb to Hill, scored a touchdown after Travis Kelce drew a defensive pass interference — and on the next drive, completed all five of his passes to take the lead.

After tweeting about his insane proclivity for comebacks, I was informed of a FiveThirtyEight article anointing Peyton Manning is the best comeback quarterback of all time. But while the piece is a great read, it has a serious flaw: it’s focused on fourth-quarter game-winning drives.

That’s an issue for two reasons. First, there are many times a quarterback can drive to give his team a fourth-quarter lead — only to see the defense to fall short and give the lead back. (The 2018 Chiefs know this all too well). Second, it ignores quarterbacks who complete comebacks that started before the fourth quarter.

Thankfully, we have a better measure: Expected Points Added (EPA) as a function of a game’s current win probability.

How do the two PMs (Mahomes and Manning) compare?

In fairness to Manning, our data set for this only includes seasons after 2008, which doesn’t include a few of Manning’s best years — particularly his first three MVP seasons. It’s very possible that with those years included, the chart would look a lot closer. However, when trailing big, Mahomes is clearly the superior quarterback when compared to Manning’s last seven seasons — which also include a few of his best years.

Sammy Watkins

As I wrote after the AFC championship win over the Titans, Sammy Watkins has been dominant in this postseason. But how does it compare wide receivers in all postseasons since 2009?

Here we see that Watkins’ playoff success probably isn’t the greatest ever. However, of the 505 wide receivers who have been targeted in the postseason since 2009, in this postseason, Watkins added more to the Chiefs chances of scoring (EPA) than all but ten of them — and played a role in boosting Mahomes’ completion percentage over expectation (CPOE).

Chiefs defense held up

Defensive performance is hard to quantify. We’ve previously done it by looking at how well the Chiefs prevent opposing offenses from completing passes relative to average — and found that the Chiefs were great at locking down the deep middle of the field.

Many have wondered, however, if this would hold true after rookie safety Juan Thornhill was lost to injury. One player who played a huge role in preventing Jimmy Garoppolo from completing a single pass greater than 20 yards downfield on Sunday was Chiefs cornerback Kendall Fuller. In fact, on Sunday, Fuller was arguably the best defensive player on the field — and to top it off, had the game-sealing interception.

So there you have it. We all get to bask in the glory of the Lombardi Trophy because the Chiefs were exactly as we thought they were — with a little extra fourth-down aggressiveness from Coach Reid sprinkled in.