ENGLEWOOD, Colo. — This year wasn’t supposed to be the Kansas City Chiefs’ year.

The Chiefs were supposed to be in a mini-rebuild after trading Alex Smith in the offseason after he was coming off an MVP-type season.

Smith’s successor, Patrick Mahomes, was supposed to be atop the NFL in interceptions, not touchdowns.

And that, my friends, is why they play the game.

On top of the Chiefs’ unblemished 3-0 record, Andy Reid’s team has passed every test they’ve faced so far in the first three weeks of the season with flying colors.

The Chiefs traded two first-round picks in order to obtain Mahomes back in the 2017 NFL Draft. The Chiefs’ offense was supposed to be good. But not now.

Through the first three weeks of the season, the Mahomes-led offense looks just as dangerous as the best offense Peyton Manning ever had back with the Broncos in 2013.

In the first three weeks of that record-breaking season — 55 passing touchdowns and 5,477 passing yards, both of which still hold their respective records — Manning was invincible, throwing 12 touchdowns to zero interceptions for a 134.7 passer rating.

Through the first three games in 2018, Mahomes has miraculously topped those numbers, dishing up 13 touchdowns to zero interceptions for a 137.4 passer rating.

Needless to say, all of those numbers are leading the league, topping the likes of Aaron Rodgers, Drew Brees, and Tom Brady — and it’s not even close, either.

In Peyton’s fourth game in 2013, the same week Mahomes is facing Denver on Monday night, he put up 327 passing yards on 82 percent completion with four touchdowns to zero interceptions with a nearly flawless 146 passer rating. Oh, the Broncos dropped 52 points, too.

Most importantly for the Chiefs, their offense, averaging a league-high 39.3 points per game, has led them to three-straight wins.

No team has started this hot on the offensive side of the ball since those 2013 Broncos, who averaged 42.3 points during the first three games.

And now the Broncos’ defense gets their shot.

“You combine a quarterback’s arm talent with the skilled players he’s throwing to and with Andy Reid’s system, it makes it a tough out. But again, we’ve played great defense here over the years, so, we’re looking forward to the challenge,” Broncos’ head coach Vance Joseph said, not letting his defense go unnoticed.

There’s no question the Chiefs’ offense so far been led by their passing attack, but their running game is no joke, either.

In fact, Kareem Hunt was the player that took the league by storm last year, leading the league in rushing (1,327 yards) on the way to his first Pro Bowl.

Denver’s defense has been stout against the run in all three games this season, not only holding opponents to 77.7 rushing yards per game, fourth-best in the league, but holding them to a 3.3 average, third-best in the league.

Last year against Denver, Hunt had two of his worst games of the season, only racking up 35 and 46 yards on the ground.

That’s why the real test on the defensive side of the ball lies with Denver’s once-great pass defense.

For years, the Broncos’ were atop the league in stopping opposing quarterbacks, but this year has been different.

In the first three weeks, Denver’s allowed Russell Wilson, Derek Carr and Joe Flacco to throw for an average of 262.7 yards per game, 11th-worst, and put up a combined 102.2 passer rating.

In front of the entire nation on Monday Night Football, Denver will be tasked with the most difficult receiving duo they’ve faced yet.

Tyreek Hill and Sammy Watkins have proved to be the perfect receivers for Reid’s offense. Not only can both receivers stretch opposing defenses deep as good as any player in the league — with Hill leading the way — they’re excellent after the catch, taking the short passes Mahomes likes to throw and making plays.

“Tyreek, he’s the fastest person I’ve ever seen on the football field,” Chris Harris Jr. stated raising eyebrows across the room, adding Hill is by far the most lethal of Mahomes’ weapons.

Oh, and there’s a guy by the name of Travis Kielce, aka the Broncos killer.

In his past three matchups against Denver, Kelce’s topped 100 receiving yards in every game, racking up an average of 131.3 receiving yards per game.

“It’s not just Patrick Mahomes, it’s their whole offense,” Harris Jr. said, understanding the task at hand.

Even in the height of the “No Fly Zone,” Denver had problems stopping opposing team’s tight ends. Nothing has changed this year, whether or not the “No Fly Zone” still exists.

The task of stopping Mahomes might be too big of a task for any team, not just Denver, but slowing him down will be the real test for Joe Woods’ unit.

Saying all of that, however, the biggest test for the Broncos is on the offensive side of the ball, specifically for Case Keenum.

And it couldn’t be more opposite of a test, either.

If the Chiefs’ offense is The Incredible Hulk, then their defense is the adorable Bambi, not wanting to get in anyone, or any teams, way.

In their first three games, they’ve done the opposite of their offense, giving up an average of 30.7 points per game, which is the third-worst in the league.

Kansas City’s defense has adopted United Airlines slogan “Fly the Friendly Skies” this season, giving up a league-worst 362.7 passing yards per game.

This is where the biggest test lies as the game sets up perfectly for Keenum to have his coming out party in Orange & Blue in front of the entire nation.

As explained here, the Chiefs’ defense isn’t as porous as the 30 points per game would indicate.

However, the real test for Keenum will be if he can move the ball effectively and turnover free if, and when, the Chiefs have a lead and the Broncos need to throw the ball.

Phillip Rivers, Ben Roethlisberger, and Jimmy Garoppolo had no problem doing just that, and the Chiefs’ defense had no problem letting them do so.

Rivers and Roethlisberger each eclipsed 420 passing yards against Kansas City.

Despite teams being down and needing to throw the ball against Kansas City’s defense, they’ve only been able to muster one total interception on the season.

Through three games, Keenum has five.

If there’s ever a game when Keenum’s going to set the stat sheet on fire — regardless of if Denver wins or loses — it’ll be Monday night, at home, in front of the entire country.

But the opportunity to light it up on the offensive side of the ball doesn’t stop with Keenum and the air-raid offense.

When opposing teams want to run the ball against the Chiefs, they’ve faced very little pushback, as Kansas City has given up 5.2 yards per carry, the worst in the league.

On one hand, Monday night’s game can’t be any more daunting on the defensive side of the ball.

On the other hand, Denver has a massive opportunity in front of them. Stop the Mahomes-Hill-Watkins-Hunt-Kelce-Reid-led offense, and the Broncos’ defense is back.

But the greatest, and potentially most important, test will be to see if Denver’s offense can be brought to life for an entire four quarters.