How the Las Vegas Raiders' surprise victory over the Kansas City Chiefs happened

The Las Vegas Raiders' 40-32 road victory over the defending Super Bowl champion Kansas City Chiefs on Sunday was the biggest upset of the NFL season so far.

The Chiefs welcomed the Raiders to Arrowhead Stadium for the 119th meeting between the two AFC West rivals. The Chiefs were 4-0 going into the game, while the Raiders were 2-2. The last three times they faced each other, KC had won each time by at least two touchdowns. Vegas oddsmakers had the Raiders as a 15.5-point underdog.

In other words, the Raiders were not supposed to win this game.

Things started off as expected. The Chiefs' two most electric playmakers -- MVP quarterback Patrick Mahomes and wide receiver Tyreek Hill -- each scored rushing touchdowns to give Kansas City a 14-3 in the first quarter.

If things continued to go that route, the Raiders were in for another bashing. That's when Raiders QB Derek Carr took the narrative into his own hands and led Vegas on a five-play, 75-yard drive that included a 59-yard TD pass to Nelson Agholor to cut the lead to 14-10.

The champs were barely bothered and promptly went on an 75-yard scoring drive of their own, capped by Mahomes tossing a touchdown to receiver Sammy Watkins. That put Kansas City back up by double-digits, 21-10.

Before the Chiefs had a chance to run away with the game, the Raiders stopped the back-and-forth by putting together two straight touchdown drives and getting necessary stops on defense. The biggest play of the sequence was Carr's 72-yard TD strike to rookie receiver Henry Ruggs III.

After a Kansas City field goal, the score was tied 24-apiece at halftime.

Both defenses actually showed up in the third quarter, as both teams went scoreless.

Las Vegas ended the drought early in the fourth quarter when running back Josh Jacobs found the end zone from seven yards out. That was the finishing touch on a 13-play, 66-yard drive that ate up eight minutes.

At that point, probably for the first time in a long time against the Raiders, the Chiefs were feeling pressure.

Mahomes couldn't get the KC offense going in the fourth quarter. The Raiders tacked on a field goal and another Jacobs touchdown -- set up by LV safety Jeff Heath intercepting Mahomes -- to go up 40-24 with about five and a half minutes remaining.

The Chiefs didn't go down easily. Mahomes hit tight end Travis Kelce for his second TD pass of the day to cut the lead to eight points.

Kansas City couldn't get the ball back from the Raiders for another chance, however. Las Vegas leaned on its run game -- namely Jacobs and Carr -- to run the clock out and complete their biggest victory of the season.

Are the Las Vegas Raiders ready to compete?

Carr was the star of the day. He finished with 347 passing yards and three touchdowns and appears to have found a go-to deep threat in the rookie Ruggs. Jacobs was solid, with 77 rushing yards and two scores.

With the defense getting key stops and takeaways against the Chiefs' high-powered offense, the Raiders were able to pull off this season's biggest shocker and make the AFC West race interesting for the time being.