Thursday didn’t exist for Kyle Shanahan and the 49ers.

They boarded a two-story jumbo jet a little before midnight Wednesday evening, and by the time it touched down in Melbourne, Australia, the sun was shining on Friday morning local time — six full days ahead of the Rams’ arrival for their globe-trotting, season-opening showdown.

The teams’ divergent travel plans will be one of the many subplots when the NFC West rivals meet on foreign soil. They both consulted experts, conducted their own investigations and surveyed their players — and came to wildly different conclusions. According to ESPN, the Rams won’t arrive until a day before the 10:35 a.m. Friday local (5:35 p.m. Thursday PT) kickoff.

The strategy worked for Sean McVay’s squad last year in London, eight hours ahead of Los Angeles. Whether it’s the right approach for the 17-hour time difference they’ll experience after flying 16 hours and almost 8,000 miles across nothing but water remains to be seen.

When the Niners sent ahead their own exploratory committee to study the effects, according to general manager John Lynch this week on KNBR, “they all said, you know, for three days you feel out of whack. You’re just not quite there.”

The Rams haven’t discussed their travel plans publicly, but according to ESPN, they did the same thing and instead “came to the conclusion that the best way to handle it would be to prepare at home, fly as close to the game as possible, let adrenaline carry them through the game and then fly right home and rest up on the back end.”

It’s impossible to know which team chose the better option as it pertains to Week 1.

But the different ways they’re going about it means at least one thing:

This game matters a whole lot more for the 49ers.

They’re the ones upending their lives for a week and doing a full reset of their body clocks.

The Rams, if all goes according to plan, will play the game as if it’s Thursday night in Los Angeles and hope their brains don’t know any better with the sun high over the Melbourne Cricket Ground. No adjustment there, no adjustment back. Just a long road trip, in theory.

The Niners, on the other hand, are almost certain to feel the effects well after they land back at San Francisco International. Jet lag affects everyone differently, so at least some portion of their roster is sure to feel the impact into their next game and beyond.

The best sports scientists and sleep experts can only do so much when, for instance, if the Niners leave soon after the game sometime Friday afternoon in Melbourne, it will be about the same time the game kicked off when they are back Friday in San Francisco.

That’s all well and good for the Rams, who will be back to their normal time zone.

But for the Niners, it would essentially be Saturday morning from where they’re coming. They’ll have a little over a week to get readjusted before hosting the Dolphins the following Sunday.

Ask anyone who’s traveled abroad: The first week back can be rough. According to Harvard Medical School, it takes about a day for the body to adjust for every time zone crossed during travel.

One could interpret that to mean the worst of both worlds from the 49ers’ perspective: They won’t have enough time to fully adjust in Australia, and they could be thrown out of whack for two weeks or more after they get back home.

Here’s the thing: You don’t have to tell Lynch.

“I remember long ago, when I was playing, we won the Super Bowl and the following year we had five preseason games, one of them being in Japan,” he said in the radio appearance. “I really felt like we were off for like multiple weeks after it. It’s not just when you’re not there.”

So even though the 49ers are greeted by arguably the lightest portion of their schedule when they return home (vs. Dolphins, vs. Cardinals), they can’t pencil in either as guaranteed W’s. That makes it all the more imperative to pick up a win Down Under.

Look no further than each team’s passenger manifest to determine how they see the stakes. The Niners took along George Kittle and Nick Bosa, both returning quicker from serious injuries, and as Bosa told NBC Sports Bay Area, “I’m flying out there, I’m going to [expletive] play.”

Meanwhile, the Rams don’t appear to be rushing Aaron Donald into uniform just two weeks after coming out of retirement. ESPN’s Dan Graziano reported this week that “a Week 2 or 3 debut looks more likely.”

Everything is pointing toward the same conclusion.

The Niners are orienting themselves around Week 1. 

The Rams’ emphasis is on the 16 games that come next.

It’s an interesting gamble, given that San Francisco will still be the underdog against a juggernaut with some of the most overwhelming preseason Super Bowl odds in NFL history.

“Yes, division games count double. Yes, it’s the Rams,” Lynch said this week. “They’re all so important. But we’re also very conscious of a long-term play.”

After all their research, Lynch said, “it became clear to us, in our mind, that the best logistics for this trip to put our players in the best position for success not only down in Australia but for the rest of the year” was to do it their way.

“We didn’t really focus on what the Rams were doing,” he said.

Only time will tell if it pays off.