BOSTON -- LeBron James said after the Cavaliers' Game 1 loss to the Celtics that shooting 3s is a part of his team's DNA.

"It's what makes us the best team we can be," he said, after the Cavs made just 15 percent of those 3s in a 108-83 beatdown at the hands of Boston.

The Cavs are where they are -- back in the Eastern Conference finals for the fourth straight year -- because of (as LeBron said) an ability to bomb 3s.

Their other staple in the playoffs has been making life difficult for Al Horford. They didn't do that either in Game 1, and it cost them dearly.

The key decision facing Tyronn Lue and the Cavs now is whether to continue to ride with the 3s or go back to stopping Horford. It means starting Kyle Korver or Tristan Thompson.

The series may hang on it.

After the Cavs were waxed by 18 points in the first-round series opener against Indiana (sound familiar?), Lue dramatically switched his lineup and put both Korver and JR Smith in there as starters. The idea was to spread the floor as much as possible, throw up a bunch of 3s and allow James to drive.

The strategy worked, with some trying moments, against the Pacers. Some of Cleveland's trouble was caused by point guard George Hill being out for 31/2 games with a bad back.

Keep in mind, though, Lue rightly started Thompson in Game 7 against the Pacers, and Thompson helped save the season with 15 points and 10 boards.

Lue stuck with the lineup against the Raptors in the conference semifinals. The Cavs made 46 3s in four games, shot .411 from out there, and Smith posted a .769 shooting percentage from deep (not a misprint).

The Cavs went with the same lineup again Sunday in Game 1 against the Celtics, obviously making the choice to stick to the 3s and maybe leave themselves exposed by Horford.

For a little backstory on him, this is Horford's fourth playoff series in as many years against the Cavs. His Hawks teams were swept in 2015 and 2016, and last year Boston won just one of five against Cleveland in the conference finals.

Horford has never made a huge impact in any of those series -- his best effort a 14.8 ppg average when the Hawks were bounced out of the 2016 conference semis. Last year, he averaged just 12.4 points and shot .456 against the Cavs in the playoffs, with 4.2 rebounds.

The constant in each of those series was Thompson, who started and gave Kevin Love some protection, especially last year against the Celtics.

Here's what happened Sunday:

Horford was awesome with 20 points on 8-of-10 shooting and six assists. The Cavs went 4-of-26 from 3-point range, and Jaylen Brown (who was matched with Korver) led all scorers with 23 points. The Celtics scored 60 points in the paint overall, attacking the rim since Cleveland doesn't really have a true shotblocker (the two best on the team are James and Thompson).

Thompson played 21 minutes off the bench and grabbed 11 rebounds to go with eight points, though the Celtics countered off their bench with giant Aron Baynes (eight boards in 25 minutes).

What to do?

"You're asking a technical question as far as something I can't control," James said. "That would be a Coach Lue question if he wants to change the lineup or not. ... The 3-point shot has been a big part since we pretty much assembled this team four years ago, and I think it's going to be a big part of it throughout the series, as long as we continue to get the ball moving and guys feel in good rhythm."

Lue didn't have much to say after Game 1, and didn't get into potential changes.

He said "we had some great shots early we didn't make, and it just kind of snowballed from there.

"Couldn't really make shots," Lue said. "Four of 26 from 3, that's not us, but they did a good job of closing out and trying to run us off the 3."

Love, who led the Cavs with 17 points and eight rebounds, said Horford is "very tough.

"And he's really good at spraying to the guy out whether it's in the corner or on the wing," Love said. "They get that swing-swing action really well and then another guy can drive it and make a play for somebody else. That's Brad Stevens basketball."

Thompson was a beast in the conference finals last season, averaging 11.6 points with 7.2 rebounds and shooting .739 from the field. The Cavs were of course a different team then with Kyrie Irving on the court -- an instant offense maker and 3-point shooter operating out of the point guard position who gave Lue the leeway to go with Thompson's defense.

Stevens said Thompson is a "great fit for that team."

"He's such a tough player to guard," Stevens said. "Especially with how much you're paying attention to all the shooters around and LeBron driving the ball.

"Baynes has kind of been our anchor down there all year anyways and I thought he did as good of a job as he can. But Tristan's hard to guard."

Starting Korver over Thompson gives Stevens the chance to start Marcus Morris instead of Baynes and stick him on James. Morris proclaimed over the weekend that he was the second-best defender against LeBron in the NBA. And on Sunday, he won his match against James, posting his first playoff double-double (21 points, 10 rebounds); and helping to limit James to 15 points on 5-of-16 shooting with seven turnovers.

Starting Thompson and playing him with James would seemingly limit Stevens' ability to use Morris. It would mean either going away from Brown or Jayson Tatum (not happening), or allowing Thompson to impact Horford as he has in the past.

Then again, the Cavs want to shoot 3s. James was 0-of-5 3-point range and is now 3-of-23 from there dating to Game 1 of the Raptors series.

Smith was 0-of-3 and Korver was 1-of-5.

Cleveland missed its first 14 3s. It's a nonstarter in any attempt to win.

"I felt like I had a couple of clean looks," Korver said. "I think maybe a few of them were kind of quick. But it's the Eastern Conference finals, you've got to make some of them."