GLENDALE, Ariz. — The choice of words Sterling Shepard used to explain what the Giants needed to do after the worst opening-game loss in franchise history are altogether fitting. 

“Got to move on from it,’’ Shepard, the longest-tenured player on the team, told The Post. “The more you let it fester, the more it can get into your brain and do negative things. You got to flush it.

You got to be able to go into the film room and be critical of yourself and move on. That’s the main thing, and not let it trickle into the next game. You got to fix everything and fix it fast.’’ 

Perfect. Reaction-wise, “flush it’’ is apropos, considering the down-the-toilet display the Giants put on the field in their 40-0 (it still looks ugly, doesn’t it?) no-show in Week 1 against the Cowboys.

It is no wonder the players and coaches were especially eager to move on as rapidly as possible, and by mid-week, any talk of that debacle was met with blank stares. 

“It’s been flushed,’’ Shepard said. “Everybody’s moved on, everybody’s ready to talk about Arizona.’’ 

Declaring you have moved on does not automatically make it so.

Perhaps it is a good thing for the Giants that they traveled darn-near across the country for their game Sunday at State Farm Stadium.

Perhaps it is fortunate the Giants will spend close to a week on the road, as they will remain in the Phoenix area and practice at Arizona State for two days before heading further north and west for their Thursday night meeting with the 49ers in Santa Clara, Calif. 

Some time away from MetLife Stadium, the scene of the season-opening football crime, might be just what the Giants need to cleanse themselves. 

The 40-point loss means the Giants are 0-1, but they could be staring at a 0-3 record before too long.

The 49ers are an NFC power and one of the top teams in the league.

Facing their ferocity coming off just four days of preparation is not ideal.

That is why it is imperative that the Giants take care of business against what is widely regarded to be a truly bad Cardinals team, which was beaten 20-16 last week at Washington. 

“Week 1, Week 5, Week 10, Week 16, we always talk about, it’s a roller coaster, but you don’t want to ride a roller coaster,” cornerback Adoree’ Jackson said. “You don’t take the highs, you don’t take the lows, but you just stay there with it no matter how good you play, stay the same or whatever it may be.’’ 

The Giants are looking for an immediate rebound as they try to divorce themselves from their opening-night flop.

Losing by 40 is rarely a harbinger of anything good, but according to the Elias Sports Bureau, there is precedent that such a rout does not have to ruin a season.

The Steelers, in their first game in 1989, were thrashed at home 51-0 by the Browns and went on to make the playoffs at 9-7.

In 1991, the Lions were beaten 45-0 in Washington and ended up in the NFC Championship game. 

This is far down-the-road stuff. In the here and now, the Giants have to get their act together, starting with putting a wall in front of Daniel Jones that does not cave in the first time a defender comes knocking.

It starts with lighting a fire on a pass rush that has too many close calls and near misses. It starts with eliminating special teams foibles that cost rather than produce points. 

“You can’t act like the sky is falling,’’ Saquon Barkley said. “That’s for everyone else to do that. But we’ve got to stay solid, the core’s got to stay solid within this locker room within this building. I think we did that, and hopefully on Sunday we can go out there and show you guys.’’