CLEVELAND — Romeo Travis plans to send LeBron James a text Sunday:

“Watch out for Frank.’’

Travis, who plays in the French League, is one of James’ best friends, dating to their high-school days in Akron, teammates at St. Vincent-St. Mary.

Last season, Travis, a power forward, and Knicks’ rookie point guard Frank Ntilikina were teammates for Strasbourg, which made the French League Finals, losing in a decisive Game 5.

Travis was delighted to hear of Ntilikina’s rousing Garden debut in which he got several ovations coming in and out of the contest Friday against the Nets. Now Ntilikina will face the Cavaliers and LeBron James for the first time Sunday.

“LeBron’s very knowledgeable about basketball, he knows about Frank and his background,’’ Travis told The Post from France. “I just hope Frank doesn’t have to guard him, though.”

Travis, who has moved on to play for LeMans, isn’t surprised about Ntilikina’s nine-point, five-assist, defensive-strong outing.

“He can score but he’s not going to score a lot,’’ Travis said. “He’s just a guy who’s going to make a team better and that’s what he did for us. He may not even get a bunch of assists, but the swing, swing, hockey assist and make the right play.’’

Injuries had hurt the perception of the 19-year-old Ntilikina, who missed summer league with a knee bruise, four of the five preseason games and two of the first three regular-season games.

“He had some small injuries here but in France there’s certain injuries you play through but they won’t let you play through in the NBA,’’ Travis said.

Ntilikina seemed jacked about facing the Cavaliers for the first time.

“It’s going to be great, but we have to go out there and play like it’s a game like the others,’’ Ntilikina said. “They are so talented. It’s going to be a fun game.’’

Travis told The Post in late June that Ntilikina asked him about the secret to James’ success.

“I tell him he’s one of the hardest-working person I’ve ever seen,’’ Travis said in June. “When he has an off-court engagement, he brings a personal trainer with him, meal plan prepared by chefs.

“He’s like, ‘I have stuff to do off the court, but I’m going to take care of what gets me there.’ ”

As much as Ntilikina’s nifty lead passes electrified the Garden, Knicks coach Jeff Hornacek was thrilled by his defense. The 6-foot-5, long-armed Ntilikina was a plus-eight in his seven-minute second-quarter stint. The Nets scored 13 points in the period.

“Going into [camp], we didn’t know if he was going to get killed on pick and rolls,’’ Hornacek said. “But after those first two practices, it was OK, not this kid. He can get around picks. He keeps fighting through them. Not something everyone can do that well.’’

After being out of the rotation the first three games, center Willy Hernangomez finally got meaningful time against Brooklyn, logging 13 minutes. During garbage time in Boston, he scored 12 points in 11 minutes, apparently opening Hornacek’s eyes.

“Everyone knows I can score,’’ Hernangomez said. “I think that game helped me but every day in practice, I showed him I’m really ready to play. I think that’s what they see. Hopefully I play 15, 20 the next game.’’