DALLAS — Luka Doncic’s message is simple for the struggling 3-point shooters around him, and with Dallas trailing Boston 2-0 while coming home for the NBA Finals.

“Just one thing: Keep shooting,” Doncic said. “We all believe in those shots. That’s how we came to the Finals. That’s how we played the whole season. We believe in those guys.”

Dallas faces several daunting numbers going into Game 3 on Wednesday night.

The Celtics are on a nine-game playoff winning streak, a franchise record in pursuit of an NBA-best 18th banner. Just five of the previous 36 teams to face this deficit (14%) have come back to win the title.

One number has to change for the Mavs to rally. Players not named Doncic are 5 of 32 from beyond the arc, with Kyrie Irving misfiring on all eight attempts.

When it comes to 3s, the supporting cast is just about as important as Irving. P.J. Washington Jr., a catalyst for the deep playoff run with his deep ball and defense, is 1 of 8. Derrick Jones Jr. is 1 of 5.

Doncic, who is 8 of 21 from deep, is the only Dallas player with more than one bucket from 3. His role-playing partners have to figure out how to produce without forcing things.

“I think it’s just taking good shots, taking open ones,” said Washington, who shot 47% from 3 in a second-round victory over top-seeded Oklahoma City but is at 23% since then. “Obviously we haven’t been making shots. We feel pretty good coming home. It’s all about just making open ones, taking open ones.”

Let’s not forget the the defense of Jaylen Brown, Jayson Tatum and Jrue Holiday, among others. Boston had the second-best defensive rating in the regular season, and has the size and tenacity on the perimeter to make Doncic and Irving uncomfortable.

While Doncic just had the first playoff triple-double in Dallas history with 32 points, 11 rebounds and 11 assists in a 105-98 loss in Game 2, the five-time All-Star has 12 turnovers in the series. Irving is shooting 35% with significantly more shots (37) than points (28).

Brown has guarded both, often picking up Doncic at halfcourt and occasionally poking the ball loose for easy buckets the other way.

“He’s been one of the emotional leaders on the team,” Irving said of his former teammate. “Defensively, he’s making it difficult. For the past few years he’s tried to make his mark on that end. When you take pride in what you do on the defensive end, it’s going to show.”

Dallas has been outscored 39-25 in points off turnovers against a team that struggled with those miscues in a six-game loss to Golden State in the NBA Finals two years ago.

“I sound like I’m repeating myself,” Mavs Coach Jason Kidd said, “but if we can take care of the ball and not give them live-ball turnovers where they are not just laying up the ball or dunking, it puts us in a better seat. We’ve got to take care of the ball. That’s the next step in the series.”

The Celtics had a 2-1 series lead in 2022 before losing three straight to the Warriors. Part of where they are now started with where they ended up against Stephen Curry and his teammates.

“It’s almost like you’ve got to trick your mind almost in a sense,” Brown said. “You’ve almost got to play like you’re down 0-2 rather than up. That’s hard to do.”

Everything about the Finals is new for Doncic, including the 2-0 deficit. Not for Irving, who is in his fourth title series and won a championship with LeBron James in Cleveland in 2016 when the Cavaliers erased a 2-0 deficit against the Warriors.

Or for Kidd, the point guard when Dirk Nowitzki led Dallas to its only championship 11 years ago. Those Mavs won three straight to close out Miami in six games.

“A lot of it is just a learning curve for myself for my teammates, and also a peace of mind that we give each other that we want to give ourselves a chance by leaving it all out there on the floor,” Irving said. “That’s literally been the focus since Game 2 ended.”

In this series, Doncic added a chest contusion to the sprained right knee and sore left ankle he’s been dealing with most of the playoffs.