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.

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.