Alex Smith and the Kansas City Chiefs are left searching for answers after following a 5-0 start with a 1-4 stretch. (Kathy Willens/Associated Press)

EAST RUTHERFORD, N.J. — Remember when the Kansas City Chiefs were the NFL’s best team and their quarterback, Alex Smith, was a league MVP front-runner?

Remember when a revved-up offense featuring rookie tailback Kareem Hunt, speedy wide receiver Tyreek Hill and matchup-nightmare tight end Travis Kelce had the Chiefs positioned as a viable Super Bowl contender and a legitimate threat to the New England Patriots and the Pittsburgh Steelers for AFC supremacy?

Nope. No one else does, either.

It wasn’t so long ago that the Chiefs were beating the Patriots in a stunning opening night upset in Foxborough, Mass., on their way to a 5-0 start to the season that made them the final team in the league to suffer a loss.

But a month and a half can be a virtual lifetime in such a week-to-week league, in which each Sunday seems to provide total vindication or a complete repudiation of everything that a team is about. And, by that measure, it has been a long time since the Chiefs have resembled an NFL heavyweight. Their dominance is a fading memory.

They have a record of 1-4 since their 5-0 beginning. The indignity became overwhelming Sunday at MetLife Stadium, when the Chiefs suffered a 12-9 overtime defeat to the New York Giants, a team that had been accused of quitting on its season and on its beleaguered coach, Ben McAdoo.

The Chiefs were left searching for answers.

“You have to get yourself through this, stick together and do better,” Coach Andy Reid said at his postgame news conference. “That’s what you have to do. . . . It’s tough to win in the National Football League. There’s parity. It doesn’t matter if you’re 1-8 or whatever it might be. There’s opportunity. You have to bring your A game every week. And we have to get ourselves back to playing better. It’s my responsibility to do that.”

The Chiefs were limited to a trio of field goals by a Giants defense that, until Sunday, rarely had resembled last season’s version. Smith had several throws that were inexplicably far off target. Hunt and Hill were lacking in big plays, aside from one 38-yard catch by Hill. The offense revolved around Kelce, who was productive but not quite good enough.

So has the league figured out the Kansas City offense? The Chiefs said they don’t think so. They don’t believe that they are seeing the same looks from opposing defenses week after week lately and being stymied, they said.

“It’s hard to say,” Smith told reporters after the game. “I don’t think there’s anything at this point that’s glaring, that every defense these past few weeks is playing us a certain way. They’re all different. They’re all doing their own thing. . . . I certainly think the focus is coming back to us a little bit.”

Whatever the case, it’s clear that the Chiefs are not the same dynamic team that they were early in the season. They are not being threatened in the AFC West, which does not have another team even at .500. But the Chiefs have failed to keep pace with the Patriots and Steelers, who have separated themselves from the rest of the conference and appear destined to meet in another AFC championship game.

Reid is a bye-week master. His teams had gone 16-2 in their first game after a bye — until Sunday. This time, even the extra week between games couldn’t help Reid get the Chiefs fixed. Since their 5-0 start, the only team the Chiefs have beaten is the reeling Denver Broncos.

The schedule is not imposing the rest of the way. The Chiefs’ final six games of the regular season come against the Buffalo Bills, New York Jets, Oakland Raiders, Los Angeles Chargers, Miami Dolphins and Broncos. There is not a team in that group that currently is above .500. But, then, the Giants had a 1-8 record entering Sunday’s game, and that didn’t help the Chiefs.

A Super Bowl-bound team doesn’t have such a misstep. The Patriots and Steelers are getting better. Both had impressive victories this weekend. The Chiefs are being exposed as a pretender.

It could make for an interesting decision at some point for Reid. Smith’s future in Kansas City has been uncertain since the Chiefs used a first-round pick in this year’s NFL draft on quarterback Patrick Mahomes. He is the future at the position. Smith kept that discussion on hold while playing at an MVP level in the season’s early stages and making the Chiefs resemble an elite team. But they don’t resemble that now.

Has Smith’s play earned him the rest of the season to try to work things out and keep Mahomes on the bench? That remains to be seen. The conversation about whether the time has arrived to make the switch to Mahomes certainly will be held by the opening of next season, at the latest.

For now, the Chiefs have a season to try to salvage. It’s not looking particularly promising. This is a team that looks fully capable of reaching the playoffs but completely incapable of being the AFC’s final team standing.

“The important thing is that everyone sticks together and keeps working,” Reid said. “The locker room has that characteristic. We have to make sure we do that. And as coaches, we have to make sure we’re putting guys in the right position. When you’re in the position, you have to make a play. . . . We all have a piece of that.”

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