Are the Sixers built to win in the playoffs without Joel Embiid? Do they have a chance against Boston?

The 76ers keep telling us everything will be fine.

Even though James Harden is in a shooting slump and Tyrese Maxey struggles against the Boston Celtics, the Sixers remind us of their relentlessness.

Yet this task is bigger than anything they’ve been through before this season. Not only are they facing a Celtics squad that’s had their number, they may do so without presumptive league MVP Joel Embiid early on.

» READ MORE: Can the Sixers make the necessary adjustments to beat Boston without Joel Embiid?

The Sixers will face Boston in the Eastern Conference semifinals with Game 1 set for 7:30 p.m. Monday at TD Garden. Embiid is still listed as doubtful with a sprained right knee. On paper, Philly has no chance of beating the Celtics in the best-of-seven series without Embiid.

Still, Harden spoke confidently following Sunday’s practice. So what gives him the confidence to believe they can beat Boston?

“Us!” the point guard said. “Like our mindset of just going out there and being us. We’ve done it all year long. Spacing the floor, attacking them, being ultra-confident.

“That’s all it is in the playoffs. If you have confidence, you can go out there and beat anybody. We’ve seen it so far this year.”

Harden is talking about the Sixers’ 12-5 record without Embiid. None of their opponents, however, were the caliber of the Celtics, last season’s NBA Finals runners-up. And they needed a 52-point, 13-rebound effort from Embiid to beat Boston, 103-101 on April 4. The Celtics were without All-Star Jaylen Brown and standout defender Robert Williams III in that game. That was their only victory over the Celtics in four meetings.

But there is some optimism that Embiid could return at some point this series.

The 7-foot-2, 280-pound center participated in post-practice shooting drills with Harden on Sunday. It was the first time Embiid performed that type of workout since spraining his lateral collateral ligament on April 20 in Game 3 of their opening-round series with the Brooklyn Nets.

He moved fluidly in the workout and didn’t require a brace on his knee. But he still hasn’t practiced since suffering the injury. Before Sunday, Doc Rivers said all Embiid was able to do was light shooting.

» READ MORE: Sixers’ Joel Embiid could be named MVP on Tuesday

“He did a little bit more,” Rivers said. “Not much. He didn’t do any running or anything like that but just did some shooting. So he’s better. He’s progressing.”

Monday will mark the ninth day since the Sixers clinched their opening-round series against the Nets. They hoped that would have been enough time for Embiid to get ready for Game 1.

“But just a little adversity to get out there and play well for Game 1.” Harden said, “Get off to a really good start and just give them four quarters of just toughness on both ends.”

While they want to generate offense by attacking, the Sixers intend to make things difficult for the Celtics defensively. Not just for All-Stars Jayson Tatum and Jaylen Brown, but for Boston’s role players, too.

“It’s going to be a really good game for us,” Harden said.

But the 10-time All-Star, who’s dealing with left Achilles soreness, hasn’t shot the ball well late in the regular season or in the first-round series against the Nets. Harden shot 34.3% against Brooklyn — including making just 9-of-34 two-point attempts.

He said his Achilles is fine. And with Embiid out, Harden expects to be more aggressive.

“We have to generate points,” he said, “so get to the basket, shoot my shot, just be more aggressive.”

The Sixers also have to get Maxey more involved. The shooting guard averaged just 10.0 points on 35.4% shooting in this season’s four games against the Celtics. He made just 21.4% of his three-point attempts.

The Sixers know they’ll need a group effort to beat Boston without Embiid. Unheralded players must step up. But the team must also play unselfish basketball, make the right decisions, play with a physicality, limit the turnovers, and get easy buckets.

In regard to Embiid, he and Harden have communicated often over the past few days in regard to what the team’s best player is going through.

» READ MORE: Sixers’ Joel Embiid (knee) is doubtful to play in Game 1 against the Celtics

“It’s up to him when his body feels like he’s ready to come back,” Harden said, “or even if his body isn’t 100%, he’s still like ‘I’m gonna go out there and hoop and try and figure it out.’ so that’s all on him.

“I think nobody in the world can have that mindset other than Joel.”

Harden and his teammates know the value Embid brings to the team. They’ve had a first-hand view of his domination.

“So when he’s ready to come back and hoop, he feels like he’s ready, obviously, we’ll be waiting for him,” Harden said. “Until then, we gotta go out there and try and win a basketball game. One game at a time. So that’s our mindset as a team.”