Jonathan Casillas of the New York Giants reacts after a...

Jonathan Casillas of the New York Giants reacts after a sack of the Bengals' Andy Dalton late in the fourth quarter at MetLife Stadium on Monday, Nov. 14, 2016, in East Rutherford, New Jersey. Credit: Jim McIsaac

Next up on the Giants’ schedule: complacency.

That’s always the next opponent for winning teams. The Giants may not know that, because so few of them have ever been part of a successful NFL season. Monday’s win over the Bengals marked, for the majority of them, their first four-game winning streak with the team. Only six players were even around the last time the Giants (6-3) were three games over .500. Just 10 of them have ever won more than six games in a season with the Giants.

The Giants have shown they have learned how to win games, and close ones, too. This is the first time since 1988 they have won two regular-season one-point games, and their six victories have come by a total of 21 points. For a team that lost so many heartbreakers last year, that’s a tremendous change in identity.

Now, though, they must figure out how to handle winning, and do it against some of the biggest losers in the NFL.

The Bears are 2-7 and the Browns are 0-10, so there is no reason why the Giants should not be 8-3 when they head into December and January for five games — against the Steelers, Lions and all three NFC East rivals — that will determine whether they will make the playoffs for the first time since 2011.

“We like the position we’re in, we’ve got to keep going, though,” Eli Manning said. “We can’t slow down. We can’t relax for a second.”

So never mind those abysmal records of the next two teams. Don’t consider how many key players the Bears will be without Sunday at MetLife Stadium, such as suspended receiver Alshon Jeffery or starting guard Kyle Long (ankle). Forget about the Browns’ losing streak, which is 13 going back to last year (they’ve won once in their last 21 games, by the way).

“We can’t look at that,” center Weston Richburg said. “It’s the NFL. There are players on every roster.”

The Giants used to be on the other side of that dynamic as potential spoilers. Now they must defend against those who want to make a statement, albeit one too late to salvage their own seasons.

Jonathan Casillas, the defensive captain, is a two-time Super Bowl champ with the Saints and Patriots, so he understands what it takes not just to beat good teams but to beat bad ones as well.

“Everything is in front of us,” Casillas said. “We’re not worried about anybody else, we’re worried about us. We’re doing good, man. We want to keep this thing going.”

Ben McAdoo, who was part of a Packers Super Bowl run, appears to be doing a very good job brainwashing his players about taking things one game at a time, focusing on day-to-day improvements, and not getting too far ahead of themselves. It would be easy for them to assume — as many outsiders do — that 8-3 is a fait accompli. Instead, they barely took time to relish their latest victory before turning their attention forward.

“It was a big win, we needed it,” cornerback Janoris Jenkins said Monday night. “We have to get ready for next week.”

Especially on a short week.

“Let’s enjoy this one, but let’s just do it a little bit faster than most,” McAdoo said in the postgame locker room. “Onward and upward.”

And if the Giants want to get a little ahead of themselves? Well, Odell Beckham Jr. said in a postgame interview on ESPN that the team is “really looking forward to Feb. 5 in Houston.” That’s the Super Bowl. It may seem like something one-step-at-a-time McAdoo would frown upon, but the coach actually liked hearing it from his star receiver . . . mostly because he’s been saying it himself since the first days of training camp.

“I’m glad he was listening,” McAdoo said. “That’s our goal. That’s why we come to work every day. That’s our one goal, but we have a lot of work to do before we get to that point.

“It’s good to have aspirations.”

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