The first-round playoff series between the Knicks and the Hawks officially has its first rallying cry.

Atlanta coach Nate McMillan sounded the bell that his team must “play through” the notion that the NBA “needs and wants” the fourth-seeded Knicks and the New York market featured in the postseason after missing out the previous seven years since last qualifying in 2013.

“Absolutely, I’ve talked about that to the team a lot. Basically, I’ve gone as far as saying the league wants this,” McMillan said Wednesday on a Zoom call. “They need this, New York, this is a big market for the league, and New York has been out of the playoffs for a number of years.

“And this is a team that our league, they want to see — there’s a huge fan base — and they want to see New York in the playoffs.”

McMillan cited the Lakers and the Celtics as other marquee franchises he believes the league prefers to be included in the postseason tournament, and he puts the Knicks “in that category.”

“The league wants to see it, everybody wants to see this,” McMillan said. “Even to the fact that our [opening] game was moved to Sunday, they want to see this.

“So, yes, we have talked about that, about the advantages of this situation and some things that we’re going to have to face, going into [Game 1], with everyone picking New York to win and a lot of folks wanting to see New York in the playoffs. It’s a battle, it’s a challenge, just playing New York, all that comes with it. … They’ve had a really good season, and I think the NBA is excited about having them back in the playoffs.”

McMillan clearly believes that notion should serve as motivation for the Hawks, who finished with the same record as New York (41-31) but lost the tiebreaker by dropping all three head-to-head matchups.

“Well, I’m giving it to them, and hoping they do,” McMillan said with a laugh. “Because it’s real. We’re gonna have to play through that.”

McMillan added he put the Hawks through a “heated and physical” scrimmage Wednesday, with not many fouls called in preparation for the first round.

“You just have to go through it,” McMillan said. “And you’re going to have to go from calm to emotionally drunk to back to calm. Because it’s going to be physical, it’s going to be a lot of pressure, it’s going to be a lot of calls that probably won’t go our way. And we have to be able to get back to calm and get to the next play, going into this series.”