BOSTON – It wound up the opposite of a Willis Reed moment. Joel Embiid came out of the tunnel to warm up and thousands already in the arena bowl at TD Garden immediately eyeball the Philadelphia center’s right knee.

Yes, there it was, a brace of some durability inside the long white leggings he wore. Embiid wasn’t noticeably gimpy but, after not playing for almost two weeks, he wasn’t exactly springy either.

The difference came in the results. Reed’s legendary 1970 appearance for New York in Game 7 of the NBA Finals really was a hobbled cameo, giving the Knicks just four points but all the adrenaline they needed to knock off the Lakers that night for their first championship. Embiid was in the middle of much of what happened at both ends Wednesday, yet his return from a sprained knee did nothing to prevent Philadelphia’s 121-87 Game 2 loss.

Whatever desperation the Sixers had channeled into victory in the series opener was gone. Boston was the more driven club this time, and now it all shifts to the Wells Fargo Center for two more in this Eastern Conference semifinal.

Here are five takeaways from the Celtics’ victory, with the tactical, physical and emotional adjustments in this best-of-seven just getting started:

1. Losing with the big guy

The top takeaway this time is a full reversal of Game 1’s, when winning without the big guy – that is, center Joel Embiid – was the night’s big headline. This time, Philadelphia had its newly crowned Kia MVP back but it never had any grip on the game.

Embiid’s every move and play had eyeballs all over them from start to, well, when he wasn’t around to monitor anymore. His night ended with 2:19 left in the third quarter, a flurry of concession substitutions by Sixers coach Doc Rivers to spare Embiid additional wear and tear, and all his top rotation guys any further embarrassment.

That Embiid played at all seemed to defy logic and tempt fate, what with Philadelphia already winning the opener and grabbing home-court advantage. Why not give him a couple more days until Game 3 Friday to recover just that much more from the right knee sprain that had sidelined him since April 20 in the Brooklyn series?

Rivers before the game explained the decision almost existentially – if a player’s healthy, he should play. But a more pragmatic reason emerged afterward.

“We knew there would have to be some growing pains bringing him back,” the coach said. “I’m glad we got them out of the way today.”

Embiid looked rusty, a little robotic, and the entire Philadelphia offense was out of rhythm trying to find what had worked so well all season without losing what had worked Monday night. It wasn’t natural and it wasn’t smooth, and the Celtics pounced all over that.

In the 26:37 he did play, Embiid scored 15 points, grabbed just three rebounds, took only nine shots and got to the line only eight times. The closest he got to his MVP form came at the other end in blocking five Boston shots, but getting to the rim wasn’t even the home team’s top priority.

“He didn’t seem 100% but he’s a warrior,” said Celtics guard Marcus Smart, who wound up with a right shoulder stinger and a cut lip after rolling on the parquet – and under Embiid – in the third quarter. “We don’t care if he’s 50%, 80% … he’s so tough.”

Working Embiid back into the flow in Game 2 went badly, but at least it’s better than working him back in Game 3.

2. Boston finds the rest of its attack

Conspicuous by its absence in Game 1, 3-point shooting was back in play for Boston from the opening tip. This is a team that outscored opponents by more than 13 points per game from the arc, averaging more than 42 attempts nightly. Getting up only 26 such shots in the series opener was an easy flaw to address in this one.

Jaylen Brown hit a three for the Celtics’ first bucket of the night. Next time down, Al Horford launched one and, soon thereafter, another. They got up nine in the first quarter, 13 in the second and 15 more in the third as they blew by that puny 26 on the way to 51 attempts.

The Celtics swung the ball, they penetrated and kicked, they stepped into them off the dribble, they did everything to jack up the deep ones and it paid off. By the end of the third, by which point they led 92-65, Boston had made 15 of 37 from out there. The Sixers, with four, had gotten outscored on threes by 33 points. And that was pretty much that.

The only real question was this: Knowing the Celtics were going to launch more threes, wasn’t there anything the Sixers could have done to hold that number down? Rivers said Boston’s offense was humming beyond whatever his team could limit. And it seemed clear Philadelphia’s disjointed offense didn’t lend itself to anything crisp from them on the other end.

3. Energy returns for Boston

Look, the Celtics knew they had messed themselves in blowing the opportunity to duck Embiid in the opener. They lived with it and heard about it for 48 hours. Beyond any gulp moment over what it might mean to do down 2-0 as the series shifts to Philadelphia, they were still angry and p*ssed, to use coach Joe Mazzulla’s words, right through Game 2’s final horn.

The Celtics played with more passion, they made more energy plays, they tapped into some of the urgency with which the Sixers had performed sans Embiid two nights earlier. Brown, for one, looked determined to personally attack the Sixers center every chance he got, storming into the paint, blocked shots be damned.

Defensively, Boston’s players crowded the other guys constantly. Intensity and force went all the home team’s way. “They pressured us, they denied us, they played in our air space,” Rivers said.

Marcus Smart and Grant Williams in particular tormented the Sixers with chesty defense – you could see how much Embiid was bugged by the smaller Williams getting down in the big center’s legs – then pricked them with late-clock buckets (Smart) and deflating threes (Williams).

4. Harden kept under wraps

James Harden had been a godsend for Philadelphia in the opener, turning in one of his best playoff performances — 45 points on 17-for-30 shooting, making half his 14 3-point attempts — to pick up Embiid’s sizable slack. It was a throwback display, a return to vintage Harden ways with virtually none of the downside.

That was replaced Wednesday by a guy searching, with his team’s best player back, to calibrate his contribution. He played more than 32 of the game’s first 36 minutes before he, too, was done for the night. Harden had missed 12 of his 14 shots and all six of his 3-point attempts to finish the night with just 12 points. Boston’s Brown took on the chore of getting into Harden and none of the other Sixers made the Celtics pay for that focus.

5. Depth might determine this series

Paul Reed had been pressed into a starting role for Philadelphia and had acquitted himself well as Embiid’s understudy. But after his double-double impact Monday, Reed was more muted. And his return to the Sixers’ reserve corps meant little — the four main bench guys in Rivers’ rotation combined for only 14 points.

Boston’s bench blew that effort out of the harbor. The three backups on whom coach Joe Mazzulla relies the most scored 37 points. Role players traditionally fare better at home in the playoffs, so Philadelphia will be hoping De’Anthony Melton gets closer to the 17 points he scored in Game 1 than his dreary two-point showing this time.

But Malcolm Brogdon — 23 points, 6-for-10 on 3-pointers — was the Kia Sixth Man of the Year this season for a reason. And if there were such things, Boston could make a solid case for Robert Williams III as Seventh Man and Grant Williams as Eighth Man. The Sixers’ counterparts can’t match their contributions on both ends on a consistent basis.

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Steve Aschburner has written about the NBA since 1980. You can e-mail him here, find his archive here and follow him on Twitter.

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