KANSAS CITY, Mo. – The smell of the victory cigars wafted down the tunnel beneath Arrowhead Stadium, straight from the Las Vegas Raiders in the celebratory visiting locker room to the despondent home locker room of the Kansas City Chiefs.

For one, the scent of success. For the other, the stench of a sloppy mess.

Taking advantage of two defensive touchdowns for the second straight week, and riding an aggressive mindset that shut down Patrick Mahomes and the rest of the Kansas City offense, the Raiders held off the Chiefs 20-14 on Monday to not only deny their longtime AFC West rival another division crown but keep their postseason hopes alive.

“That was one of our mantras,” Raiders interim coach Antonio Pierce said afterward, “by any means necessary.”

That meant big defensive tackle Bilal Nichols returning a fumble 8 yards for a touchdown, and Jack Jones taking an interception 33 yards for another score 7 seconds later. It meant Aidan O’Connell never completing a pass after the first quarter, yet also never making the same mistakes that Mahomes made for Kansas City on a soggy Christmas Day.

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The Raiders (7-8) became the first NFL team since 2000 to win without completing a pass after the first quarter, and only the fifth team to beat the Chiefs at Arrowhead Stadium without scoring an offensive touchdown.

“Obviously this was a huge game. It’s a rivalry game,” O’Connell said. “We play them twice a year, every year, so to come into Arrowhead Stadium and win a game like this, it’s pretty awesome. It’s pretty special for our guys.”

Kansas City (9-6) hardly helped its cause: Along with allowing the two defensive TDs, Harrison Butker missed a chip-shot field goal, penalties and dropped passes were again a problem, and twice they failed to convert on fourth down in the second half.

“They played a better game than we did today,” said Chiefs coach Andy Reid, whose team has lost three of four. “On offense we struggled. That’s my responsibility to make sure we put the guys in the right position to make plays, and that didn’t happen the way we wanted it to. I take full responsibility for the way we played offensively there.”

The Chiefs still had a chance in the closing minutes Monday to clinch their eighth straight AFC West title and keep their hopes alive for the No. 1 seed.

But after Mahomes hit Justin Watson for a touchdown with 2:42 to go, the Raiders’ Zamir White broke loose for a 43-yard gain, picking up a first down that allowed them to run out the clock.

Mahomes finished 27 of 44 for 235 yards and the interception; he nearly threw a second but it was overturned upon review.

The Raiders, playing without injured running back Josh Jacobs, won despite a dismal day from their offense. White ran for 145 yards, but much of that came on the final possession. O’Connell was just 9 of 21 for 62 yards, the Raiders were 0 for 3 in the red zone and 3 for 12 on third down, and they had seven fewer first downs than Kansas City.

All that mattered was the score, though.

“That’s why it’s a team sport,” O’Connell said. “It was a team win.”

Reid had spent the past few weeks lamenting the mental mistakes that kept costing the defending Super Bowl champs, and they made more of them Monday than they had in any game this season.

They went three-and-out on consecutive series to start a game for only the second time with Mahomes at quarterback. They were held to minus-18 yards in the first quarter, the second-worst total for the club since at least 1991. And the reigning league MVP was sacked twice in those two series, while more offensive penalties only made matters worse.

The Chiefs took the lead early when Isiah Pacheco took a direct snap 12 yards for a touchdown, and Las Vegas gave the ball right back after a punt. But when Pacheco again took a direct snap and tried to hand to Mahomes, they bobbled the exchange and the 315-pound Nichols was there to scoop it up and run for the touchdown.

On the next offensive play for Kansas City, Mahomes was picked off by Jones, whose 33-yard return gave Las Vegas its fourth defensive TD in the past two weeks, along with a 17-7 lead over its longtime divisional nemesis.

Then, Jones appeared to play the Grinch when he faked giving the ball to a kid wearing Chiefs clothes in the crowd.

The defensive scores made it 17-7, and it was still that way when Butker missed his field goal before halftime. The Raiders added one in the third quarter, and that was all the scoring they needed to end a six-game skid against Kansas City.

STATS AND STREAKS

The Raiders have five defensive TDs this season, their most since 2005. … The first quarter was the best by the Raiders defense since holding the Chargers to minus-21 yards on Dec. 1, 1991. … Rashee Rice had six catches to reach 74 for the season, breaking the Chiefs rookie record of 70 set by Dwayne Bowe in 2007. … Malcolm Koonce had three sacks for the Raiders.

INJURIES

Chiefs CB L’Jarius Sneed left after making a tackle late in the third quarter. … Pacheco went into the concussion protocol in the third quarter when his helmet popped off and he was kicked in the head. … RG Trey Smith hurt his leg in the fourth quarter.

UP NEXT

The Raiders visit Indianapolis on Sunday.

The Chiefs play Cincinnati on Sunday.