FOXBOROUGH, Mass. — The Kansas City Chiefs avenged their AFC Championship Game loss, but they also sent a signal to the rest of the rest of the league: The New England Patriots are clearly not the same team they used to be.

The Chiefs shook off early miscues, including two defensive penalties, an early Patick Mahomes interception and a 7-0 deficit, then fended off a furious Patriots comeback attempt to secure a 23-16 win at Gillette Stadium.

Kansas City's victory combined with the Oakland Raiders' Sunday loss to Tennessee secured the AFC West title for the Chiefs, marking the fourth consecutive season the Chiefs have won the division and clinched a playoff berth.

"Between last year and what was at stake this year," Chiefs defensive end Alex Okafor said, "to go into Foxborough and get this win, man, it was incredible."

Chiefs right tackle Mitchell Schwartz agreed but said the team still has some unfinished business ahead.

"There's still a while to go," Schwartz said. "Beating the Patriots in December isn't really the ultimate goal for the season. It's a good game for us, and obviously it puts us in a better position for the playoffs. It's just a good team win."

Clinching a playoff berth with Oakland's Sunday loss and their own victory over the Patriots, the defending Super Bowl champions, made it even sweeter.

"You want to win against the best," Chiefs running back LeSean McCoy said. "I've been in the same conference, same division, as Tom Brady (when McCoy was with the Buffalo Bills), and he's the real deal. So, to get the win here in Foxborough, it means a lot. This right here is a great win against a great franchise."

Mahomes, who has struggled in his past two games, turned in a steady performance, completing 26 of 40 passes for 283 yards and a touchdown. He hurt his hand early but stayed in the game; Chiefs coach Andy Reid said afterward that Mahomes would have the hand X-rayed as a precaution.

Mahomes said he "kind of hit the ground weird when I was trying to throw the ball away and got hit." Asked if he had any thought of coming out of the game, Mahomes responded, "No, no, never. For me, I'm playing until they take me out."

Good thing he stayed in. The Chiefs' signal-caller hit rookie wide receiver Mecole Hardman for a 48-yard touchdown in the second quarter, and connected with tight end Travis Kelce seven times for 66 yards in the game.

Kelce added a 4-yard touchdown run following a direct snap to him in the wildcat formation.

Without Damien Williams, out with a rib injury, the Chiefs split touches in the backfield between LeSean McCoy, Spencer Ware and Darwin Thompson. McCoy led the way with 39 yards on 11 carries, while Thompson totaled four catches for 36 yards on five targets.

Kansas City's defense came up big for a third straight game, limiting the Patriots to 278 total yards of offense.

The Patriots (10-3) couldn't find an offensive rhythm en route to scoring fewer than 20 points for the third time in their past four games. The Chiefs came in with a plan, and it centered on befuddling quarterback Tom Brady. The plan worked.

The Chiefs harassed Brady, sacking him four three times and totaling six quarterback hits. Defensive end Frank Clark, who battled illness and entered the game questionable to even suit up, played in a rotational role and recorded a sack.

"It's tough trying to stop a guy like that with the weapons he's got," Chiefs linebacker Reggie Ragland said of Brady. "So, we just had to do a good job of sound defense, let the offense do what they do. But if we keep playing defense like that, I thing we have a good shot of going where we want to go."

Cornerback Bashaud Breeland came up with the defensive play of the game late in the fourth quarter. He was locked up against wide receiver Julian Edelman in the end zone, and Brady threw it across the field to his favorite receiver. Breeland got his arm around Edelman without interfering and knocked the ball away.

The Chiefs' run defense also rebounded a week after allowing a 100-yard game to Oakland Raiders running back Josh Jacobs by holding the Patriots' ground game to 94 yards on 22 carries spread out among six ballcarriers.

"It's incredible, because that doesn't happen very often," said backup Chiefs quarterback Matt Moore, who spent seven seasons in the AFC East with the Miami Dolphins. "I've been here numerous times where you got the lead and it disappears quickly, or at the end of the game they somehow find a way to win.

"So for us to play the way we did and standing on the sideline watching the defense, I mean, that was the game. That last drive was the game and for them to shut it down, it was an incredible job by them."

Long-snapper James Winchester agreed.

"Props to the defense," Winchester said. "They stepped up huge when we needed them."

The Chiefs' special teams unit came up with a big play of its own: defensive end Tanoh Kpassagnon blocked a field-goal attempt for the second straight game.

The Patriots, meanwhile, blocked a Dustin Colquitt punt in Chiefs territory to make the game interesting late. New England scored two plays later on Brandon Bolden's 10-yard run to make it 23-13 Chiefs.

A week after accomplishing a rare feat — committing no penalties in a game — the Chiefs were flagged 10 times for 136 yards against the Patriots. The Chiefs also totaled two turnovers, one by Mahomes, on an interception, and one on a Kelce fumble.

Kansas City will take those mistakes and use them as learning tools with a postseason spot now secured. The Chiefs host the Denver Broncos and Kansas City native Drew Lock in Week 15 at Arrowhead Stadium.