There are few things in the NBA more precious than time and space. Four years ago, it seemed like the Philadelphia 76ers had endless amounts of both as they faced off with the Miami Heat in a first-round playoff series with an eerily similar setup to Monday night's Game 1 of the Eastern Conference semifinals: Superstar center Joel Embiid was out with a broken orbital bone and hoping his teammates could prolong the series long enough for him to return to action with a custom-made face mask.

Ben Simmons was Embiid's running mate in 2018, when it felt like the young duo had a decade in front of them to figure out how to pay off "The Process," former Sixers general manager Sam Hinkie's then-radical vision of championship team construction.

The Heat were in the opposite predicament, short on both time and space, and trying to squeeze one last playoff run with an aging Dwyane Wade before ultimately rebuilding around a rookie on that team named Bam Adebayo.

Four years later, a lot has changed.

Miami's 106-92 win against Philadelphia on Monday at FTX Arena wasn't just a manifestation of how far the top-seeded Heat have come in their reboot, it laid bare just how little time and space this group of Sixers has left to figure out how to become a championship contender.

Simmons is with the Brooklyn Nets now, still dealing with the aftereffects of his time under the heat lamp of expectations that came with being a face of the Process-era Sixers.

His replacement, 2018 MVP James Harden, was essentially suffocated by a lack of space Monday night while trying to pick up the slack for the injured Embiid while he and his teammates missed more than 82% of the 3-point shots (28 misses on 34 attempts) they took against the Heat.

Much will be made about Harden's lack of impact in Game 1. He finished with 16 points on 5-of-13 shooting, running his streak of being held under 25 points to 11 straight playoff games, his longest since he was coming off the bench for the Oklahoma City Thunder to start his career.

Harden, 32, has noticeably had trouble getting past defenders during his time in Philadelphia, and it has prompted questions around the league: Has he lost a step? Is his injured hamstring still a problem? Can he get his burst back in time to justify a max contract extension worth $223 million this summer?

Once Embiid was lost indefinitely with a concussion and orbital fracture suffered in Game 6 of Philadelphia's first-round series win over the Toronto Raptors, the time pressure on those questions swirling around Harden sped up.

But Monday night's dismal showing was as much a referendum on the woeful state the Sixers find themselves in without Embiid as it was on Harden's current abilities, because he literally had no space to operate.

According to ESPN Stats & Information data, 12 of Harden's 13 field goal attempts were contested. He also was double-teamed nine times.

The average closest defender on Harden's shot attempts was 3.7 feet away, according to Second Spectrum; it was the third-smallest amount of separation in a game for Harden this season and the smallest amount in a playoff game for Harden in two years.

If you've followed Harden's career even a little bit, you know why this is a problem: He needs space to operate. He can create some of it himself, even without the burst he used to have, but not when the defense has no reason to respect his teammates' shooting.

"I think I can be a little bit more aggressive," Harden said when asked what he could improve on going forward. "They did a really good job of just boxes and elbows, showing their bodies and crowding the ball when the ball screens came.

"But I think the shot-making is what opens up the floor for our entire team."

The matter-of-fact way Harden delivered that assessment was as important as the order in which he plainly diagnosed what went so wrong for Philadelphia in Game 1.

First, he put some of the blame on himself. Then he gave credit to the Heat's defense. Then he said the part that really matters without throwing any of his teammates directly under the bus.

That's the bright side for the Sixers: To have any chance of getting back into this series, they'll need Harden to show accountability and leadership.

"It's one game, but things can turn fast," said Harden, who was trying to sound an optimistic note to a relatively young locker room he has been thrust into leading with Embiid out.

And there is some optimism Embiid could return at some point in this series, but that's mostly because he has been so determined to play through injuries and pain this season.

Embiid was home in Philadelphia still dealing with concussion symptoms on Monday, sources told ESPN. To even think about playing again, he'll have to progress through the NBA's concussion protocols and then get a good report back on a right orbital bone fracture at his appointment on Wednesday, the day of Game 2 in Miami.

If everything goes as well as it possibly could, sources said there is a chance Embiid could play in Game 3 or 4 in Philadelphia while wearing a custom protective mask. That's what happened in 2018, when Embiid returned in Game 3 of what turned out to be a five-game series win over the Heat and dubbed himself the Phantom of the Process.

But while the circumstances are similar this year, the feeling is altogether different.

Everything seemed wide open in front of Philadelphia back then. Their two superstars were young and still growing up and together.

There is a sense of urgency now that Embiid is squarely in his prime and Harden is trying to hold on to what's left of his. There is also a weight that wasn't there before, because of all that has happened along the way.

There is still time to figure it out. There is still space to create. But there's a lot less of it now.