Elise Amendola/Associated Press

BOSTON — As this postseason ticks along, it's important to remember that the Philadelphia 76ers are attempting to accomplish something never done before in NBA history.

Only three times since 1985, the year the lottery was instituted, have we seen a team jump from the lottery one year to the Finals the next. There were the 2001-02 Nets, a squad that traded for future Hall of Famer Jason Kidd after a 26-win season. There were the 2007-08 Celtics, who captured a championship just one season after winning a measly 24 games, but that was thanks to trades for Ray Allen and Kevin Garnett. And then there were the 2014-15 Cavaliers, who, one season after winning just 33 games, rode LeBron James' Cleveland return to a Finals run.

This Sixers team is different. By now you're acquainted with the story. Four years in the league's cellar, a process billed as, well, you know, only to reemerge from the dust as one of NBA's premier teams. The Sixers won 28 games last season. This year they racked up 52, earned a No. 3 seed, ran the Miami Heat off the floor in the first round and, with the conference around them crumbling, suddenly morphed into favorites in the East.

It's important to remember that, aside from a few exceptions containing outstanding circumstances, NBA teams never reach the peak without stumbling a few times first. It's important to remember that the Sixers' jump forward this season has been the result of organic growth and health—not an injection of shiny stars, unlike those other three examples.

It's important to remember all this as we sit back and digest the beating the Boston Celtics laid on the Sixers Monday night during Game 1 of their Eastern Conference Semifinals matchup, a 117-101 shellacking in front of a raucous home crowd.

"This was a very poor game from us and I give the Celtics a lot of credit for producing that." Sixers head coach Brett Brown told reporters afterward. "This isn't who we are. We're going to fix some things. I'm going to have to back up my words with our group and we've got practice tomorrow. But to think this game reflects who we've been the past few months would be a mistake."

Elise Amendola/Associated Press

Brown is right. The Sixers won their final 16 regular-season games. They finished the year with the league's third-best defensive rating and fourth-best plus/minus differential. They're big and long and athletic. They have a stud in the middle who might be the league's top defensive player and who also paralyzes opponents on the block. They have a Magic Johnson clone running the point. They have a plethora of snipers gunning from deep.

They also have some flaws. All teams east of Oakland do, and the Sixers now face a coach who specializes in discovering and exposing an opponent's weakness. Or, rather, doing all he can to take away his opponent's strength.

And so you end up with Ben Simmons seeing a wall of white Celtics jerseys every time he tries pushing the ball up the floor. The Sixers rely heavily on fast breaks. As talented as they are, they only have one player—Joel Embiid—who can consistently create shots for himself. Giving the ball to Simmons and having him run is one of their methods for countering this limitation, for creating clean looks from deep.

The Celtics and their top-ranked defense took away that weapon in Game 1. The Sixers pushed the ball at a rate that during the regular season would have measured as one of the worst in the league, according to Cleaning the Glass. That's not the sole reason Philadelphia connected on just five of its 26 triples. Boston's decision to guard Embiid one-on-one and not send aggressive help on Simmons drives mucked up the Sixers' entire drive-and-kick, pass-happy system.

"We didn't move the ball as we usually do," Simmons said. "And that's one of the things we need to look at and reassess."

Elise Amendola/Associated Press

A reversal of luck will close up some of these holes. Though the Celtics' defense is stout, Sixers shooters missed about a dozen open triples—looks that, going forward, are likely to fall.

It was the performance on the defensive end that could prove more telling, that should leave Sixers fans concerned. As Embiid said after the game, "It starts on defense. I thought I was s--tty. I thought we were all bad tonight. That's not who we are, definitely. When everybody is on, we're the best defensive team in the game."

There were miscues following timeouts and shooters left open. There was missing weak-side help and instances of jogging up the floor.

"It was just frustrating because we knew what we needed to do and we weren't doing it," Simmons said. "We talked about it, but we weren't doing it."

That's where youth and inexperience reveal themselves, where a team—whose longest-tenured player is the 24-year-old Embiid—can begin withering. Blunders like those have the propensity to snowball, especially for a group trying to squeeze a learning curve that takes years into a three-month period.

That doesn't mean the errors will grow for Philadelphia. Talent usually wins out in the NBA, and the Sixers are the more talented team in this series.

But in the Celtics, the Sixers face a well-coached, precise, efficient machine that pecks at mistakes like a vulture. This will be the greatest test this Sixers team has ever faced.

That it's also their first test is what will make the rest of this series so fun to watch.

Yaron Weitzman covers the NBA for Bleacher Report. Follow Yaron on Twitter @YaronWeitzman, listen to his Knicks-themed podcast here, and sign up for his newsletter here.