Inevitable as the Chiefs’ 27-20 victory over the Raiders on Sunday at Allegiant Stadium might have seemed by the end, it also hinged on a crucial inflection point — and on freshly compelling testimony to what should be abundantly evident by now:

As much as this rightfully will always be considered the Patrick Mahomes Era, the Chiefs’ defense is the most steadfast asset for a team whose very identity now is complementary football.

Sometimes that means one aspect enhancing another; other times, it might mean one counterbalancing, or even atoning for, another.

Like the defense did Sunday to enable the Chiefs to win their franchise-record-tying 13th game in a row and lift them to 7-0 for just the third time in team history.

Look, maybe the Chiefs would still have won this game if not for the majestic goal-line stand when everything seemed to be disintegrating. And, sure, there were dozens of other moments that helped create the outcome.

Just the same, it all was in jeopardy at the pivotal juncture before the KC defense reset the game — the latest reminder of how this team rolls.

After taking a 17-10 halftime lead, the Chiefs careened into an atrocious stretch to start the third quarter. And the Raiders cut their lead to 17-13 as the Chiefs were self-destructing.

They were nabbed for five penalties in 14 plays and three in a row before a Mahomes pass from the Kansas City 2-yard line was deflected into an interception by Tre’von Moehrig and returned to the Chiefs’ 3.

Instead of crumpling then, what happened next was the stuff of legend.

“Unbelievable,” coach Andy Reid said.

On first down, George Karlaftis and Drue Tranquill took down Alexander Mattison at the 1. On second down, it was Karlaftis and Nick Bolton credited with the tackle for no gain. On third and goal from the 1, Tranquill and Bolton smothered Mattison for minus 2.

Then came the defining play of the series and, arguably, the game:

With quarterback Gardner Minshew back to pass, Karlaftis plowed Raiders right tackle Thayer Munford Jr. back toward Minshew. And when Minshew tried to step up and away, the oncoming Tershawn Wharton was there to smack him down for a 5-yard loss.

“George made a great play …, and I kind of walked into it,” said Wharton, enjoying the best year of his career in his fifth season and adding, “You go for it on fourth down, we’re going to make you pay.”

Especially, he said, because the defense had been upset over how it played in the first half and was “on fire” for the second half.

That assertion also seemed reflected in limiting Las Vegas to a field goal on the previous series — after the Raiders had taken over at the Kansas City 28 because of a big punt return aided by a penalty on the Chiefs.

As we kept talking, Wharton then added a point so subtly I didn’t really realize what he said until I listened back to the interview.

After what he quite correctly called a momentum shift, he said, “our offense went out and continued to feed off of us.”

Think about that a second.

Quite a switch from what this once was: an offensive juggernaut and a defense that was just good enough to be a net positive.

But in a number of ways, Wharton’s thesis has become a prevailing dynamic over these last two seasons with the Steve Spagnuolo-guided defenses that have been among the best in the NFL.

Last season, the Chiefs’ defense finished second in the NFL in both points and yards allowed.

And while the statistical status isn’t quite as gaudy this time around — the Chiefs entered the day fifth in points allowed and 10th in yards surrendered — this team’s defense has become a compelling and decisive force in virtually every game.

Take it from Mahomes, who knew the tipped pickoff put the Chiefs “in a terrible position.”

It would have been easy for them to sag in that sudden-change situation, he said, because of an offensive gaffe.

“But they stood their ground,” Mahomes said. “They went out there and said that they’re going to make them earn it. They’re going to make them earn every single yard.”

And then some, as it happened, courtesy of a defense that had five sacks and held the Raiders to 33 rushing yards

The flip side of all this is that the Chiefs’ offense had to do its part to make that count.

And indeed it did with another demoralizing kick in the teeth to the Raiders: an 8-minute, 43-second drive that consisted of 19 plays, covered 87 yards and culminated in a Harrison Butker field goal that made it 20-13 with 8:44 left.

Then came a forced fumble by Mike Pennel recovered by Tranquill to give the Chiefs that ball at the Raiders’ 38.

When they promptly converted that into Mahomes’ 9-yard touchdown pass to Worthy for a 27-13 lead with 4:59 to go, the outcome was virtually sealed.

And it all reiterated why the Chiefs are the only undefeated team in the NFL — and why they are in prime contention to become the first team to win three straight Super Bowls.

Because of Mahomes, yes, and Reid’s ingenuity and the guile of general manager Brett Veach — whose trade for receiver DeAndre Hopkins immediately paid dividends on Sunday (the veteran pass-catcher had two catches for 29 yards and showed all sorts of signs of what he could do with Mahomes).

But also because of a defense that is the essence of what these Chiefs are: a gritty, resilient find-a-way team that epitomized it with an ultimate statement in the trenches.

Part of a symbiotic connectivity that makes this team greater than the sum of its considerable parts.

“I think the biggest thing about the defense, about this entire team, is whenever your number is called, the guys want to step up and make the play …” Mahomes said. “We lost all the momentum, and they were in a bad situation, and that whole entire unit stepped up when their number was called to make a big-time stop. And that’s what it takes (to have) great football teams.

“It takes greatness from everybody. It can’t be one guy. And that’s what’s made us so great for so long, throughout my career: It’s not all about me, it’s not all about Travis (Kelce), it’s about this entire team. And that’s what makes it so special.”