BOSTON — We still don’t know when but we finally officially know who the Boston Celtics will face when the first round of the NBA playoffs begins next weekend.

With the Celtics and Indiana Pacers both losing Sunday, the two teams will now face off as the East’s fourth and fifth seed, respectively. That means Boston will have home court in the opening round.

“It’s really hard,” Coach Brad Stevens said of facing the Pacers, a team they’ve just played twice in rapid succession, in seven-game series. “But everything in the playoffs is really hard. Always has been and my hope is that we can, obviously, coming out of (Sunday) be fully healthy and go to work, and be ready for them. But w’eve got one more game, and you know, we’re looking forward to the challenge in Washington on Tuesday.”

The obligatory pleasantry thrown Washington’s way aside, Boston has a great challenge ahead in facing the Pacers. Sure, they’re without Victor Oladipo and they’ve struggled a bit lately without a star to carry them, but possibly seeing a team so often in such a short amount of time means there are few surprises about each other.

“Both teams have been able to (prepare) so it’s not like there’s an advantage, right?” Stevens said. “I think ultimately we both, us and the Pacers, have pretty much known we’d be the matchup. Didn’t know where the games would start. I’m not sure that’s a big deal. I think the biggest deal is how you play when the ball is tipped. It’s going to be an extremely tough series. It’s going to be an extremely physical series. I did not think they played their best without (Darren) Collison the other night. We expect a lot of games like that game two weeks ago here, 10 days ago here.”

That one boiled down to Kyrie Irving being a hero, which is why Boston seems to have an edge in this series. When the game gets tough, it’s the stars who step up and help win.

Still, there was plenty for Boston to learn from that game and even their win Friday night at Indianapolis. Boston nearly gave away the game at home by not getting to loose balls and giving up 20 second-chance points on 14 Pacers offensive rebounds.

“It’s often a blockout error. It’s often a ‘did you block him out early enough’ error if you’re small,” Stevens said. “That’s especially important as you get into the Pacers game because those guys crash the glass as well as anybody and make it really difficult.”

“I think it’s really been about focus. Our focus and that sense of urgency, that for whatever reason, we haven’t had as a group all year,” said Al Horford of the Celtics. “I think that we all understand how we need to play and we know in order to have any chance against Indiana, we have to be at our best.”

Being at their best hasn’t been easy for the Celtics. They’ve been doing it more often lately but complete games with full focus have been rare. Playoff success skews towards stars, but also highlights a team’s habits, good and bad.

“Obviously there are going to be some runs out there in the playoffs and high-level basketball,” Irving said. “Guys are going to be making some incredible shots and we just want to limit them to their tendencies, and just play well. Every shot is not going to go in, but we’ve just got to be able to be resilient and just have some fun out there. Don’t let the pressure of the moment get the best of you, and just go out there and hoop.”

Irving has been looking forward to the playoffs for months, which may seem to put a bit of pressure on him now that they’re here.

So many of Boston’s faults were dismissed by the players by promising that things can or will be different come playoff time. The loss of focus and persistent implosions, we have been told, aren’t as likely to happen when the focus is on one team at a time, when the schedule finally breaks and a team can be in one city with time to rest and travel and sleep like normal humans.

For Irving, the arrival of the playoffs gives him and his teammates a chance to be something they haven’t been for much of the regular season.

“Just be great. Just be great. It’s easy to do that when you put in the work and do what you’re supposed to do,” he said. “Take care of your body, just go out there and play. I’m just happy that we get to prepare for a team for multiple days. It makes it a lot better to go out there and just make plays within the game. There’s nothing that’s really surprising out there in the playoffs, so just get a good feel of the Pacers. Game 1 is a feel-out game and then we go from there.”