Patrick Mahomes Kansas City Chiefs
Patrick Mahomes #15 of the Kansas City Chiefs talks with Marquise Goodwin #11 of the San Francisco 49ers after the game at Arrowhead Stadium on September 23rd, 2018 in Kansas City, Missouri. David Eulitt/Getty Images

There hasn’t been a bigger story in the early part of the 2018 NFL season than Patrick Mahomes. The second-year quarterback is the easy choice for MVP through three weeks, playing nearly perfect football and helping to make the Kansas City Chiefs the Super Bowl favorites in the AFC.

Mahomes, of course, can’t play this well forever. Even if he somehow proves to be the best signal caller in the league, a pace of 69 touchdowns and no interceptions clearly isn’t sustainable.

When will Mahomes and the Chiefs finally come back to earth? There are reasons to believe it’ll happen in front of a national audience in Week 4 when Kansas City visits the Denver Broncos on “Monday Night Football.”

Coming off a loss in Baltimore, Denver is off to a 2-1 start this season. A win against the Chiefs would put them tied for the best record in the AFC West, though they’d technically have the edge over Kansas City because of the head-to-head tiebreaker.

Denver returns to Mile High, where they defeated the Seattle Seahawks and Oakland Raiders in consecutive weeks to start the year. The Broncos have one of the best home-field advantages in the NFL. They are 16-7 in their last 23 home games and 12-5 in their last 17 home games against the Chiefs.

Monday will provide Mahomes with the most difficult test of his young career. He did start the season with a win on the road against the Los Angeles Chargers, though L.A. has no home-field advantage to speak of. The 23-year-old torched a bad Pittsburgh defense on the road in Week 2, and the Chiefs cruised to a win at Arrowhead Stadium over the San Francisco 49ers last week.

Mahomes has exceeded all expectations with 13 touchdown passes and no interceptions. His 137.4 passer rating is well ahead of Alex Smith’s 104.7 rating that was first in the league last season. He’s only been sacked four times, tying him for 28th in the NFL.

Case Keenum, on the other hand, has not been the quarterback Denver hoped they were signing. Asking to get the same player that had a career-year with the Minnesota Vikings in 2017 was probably not realistic, but hoping that Keenum could do better than five interceptions and a 71.6 passer rating through three games was more than reasonable.

There might not be a better team for Keenum to face as he tries to put together his first impressive performance of the season. The Chiefs are 30th in opponents’ yards per play and tied for last in opponents’ passing yards. Opposing quarterbacks have put together a 106.3 passer rating against Kansas City, who has given up at least 27 points in each game.

Scoring 27 points against the Chiefs probably won’t be enough to win, and it might not even be good enough to cover the spread. Kansas City is a 4.5-point road favorite, according to the latest betting odds at OddsShark, and the over/under is 55. The Chiefs have scored at least 38 points in every contest.

The Broncos should be able to put more pressure on Mahomes than he’s seen all season. Von Miller remains a top pass rusher and No.5 overall pick Bradley Chubb is proving why he was drafted so high. It’s going to be difficult for Mahomes to have another 300-plus yard performance with several touchdown passes and no interceptions against a talented defense in a tough environment.

But Mahomes doesn’t have to be nearly as effective as he’s been in order for Kansas City to remain undefeated.

The Broncos’ defense has been a disappointment in the early going, allowing both Derek Carr and Joe Flacco to lead their offenses down the field without much problem. The unit will have to deal with Tyreek Hill, who has turned himself into one of the league’s best receivers, as well as Travis Kelce, who’s better than any tight end not named Rob Gronkowski.

Because Kansas City’s defense has been so bad and Mahomes is bound to regress, at least somewhat, Denver can keep this close at home. It’s just hard to pick the Chiefs to lose until they face a defense that's proven to be one of the league’s best.

Prediction: Kansas City over Denver, 30-28