After a game last December, Kristaps Porzingis was handed a piece of paper with a phone number on it. A basketball legend was impressed with how the young Knick played and carried himself, and he wanted to extend a helping hand.

It was Dirk Nowitzki.

Porzingis is from Latvia. He idolized Kobe Bryant, but he also looked up to and admired Nowitzki, who grew up in Germany. Now the best European-born NBA player and future Hall of Famer wanted to exchange numbers and texts with the unproven rookie.

“I’m here if you need me, kid” essentially was Nowitzki’s message to Porzingis.

“He said, ‘Whatever question you have, whatever you need, let me know, and if you want to work out during the summer, we can make that happen,’ ” Porzingis said.

“It was really nice of him to give back and to help young players from Europe like me to get to that next level. It meant a lot. It’s an honor that he reached out to me and gave me that opportunity. It just didn’t work out.”

Nowitzki, 38, tried to arrange the workout in September, but it didn’t fit their schedules. Nowitzki was in Germany and would be returning to Dallas. Porzingis, 21, considered going, but he already had begun working out with the Knicks and many of his new teammates and didn’t want to leave them so close to the start of training camp.

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They will try to get together after this season. Porzingis hopes to learn “a signature move” from Nowitzki, whose one-legged fadeaway jump shot has helped him score more than 29,000 points and win an NBA championship and league MVP award.

“I love the kid,” Nowitzki said. “I really wanted to train with him over the summer, but it didn’t work out. Hopefully we can do something next summer.”

The Mavericks will visit Madison Square Garden on Monday night, and Porzingis and the Knicks will try to end a two-game losing streak. It also will be a chance for Porzingis and Nowitzki to talk in person and continue what started after their first meeting last season, Dec. 7 at the Garden.

For Porzingis, it was a memorable night in more ways than one. He scored 28 points and Nowitzki had 25 in the Mavericks’ win. After the game, Nowitzki had a ball boy give Porzingis his phone number and ultimately told him he would help him any way he can.

“That game you could see I wanted to score on Dirk and he wanted to do the same thing on me,” Porzingis said. “But it was really nice that he did what he did for me and showed respect. I think what he saw in me is not that I’m talented, but my work ethic and the type of guy I am. That’s what he liked about me, so hopefully I can learn from him in the future.

“Knowing that Dirk is going to be at least two more years in the league, hopefully I have that opportunity next summer.”

When Porzingis was growing up and playing in Europe, he studied Nowitzki’s game, and has been compared to him more than any other player. The 7-foot Nowitzki helped usher in the era of “stretch-fours,” big men who open the floor with their shooting range. The 7-3 Porzingis fits that mold and looks forward to getting some pointers from an all-time great.

“His turnaround jump shot is unguardable, basically,” Porzingis said. “That’s one thing I can work on and maybe steal a move or two from him and add to my game. A signature move, I’d like to see if I’m capable of doing that.

“There are a lot of little details I can ask him about the game, about off-the-court stuff. He’s been in the league forever. From a guy like that with a lot of experience, there’s a lot to learn. I hope I have that chance.”

Jennings fined. The NBA fined Brandon Jennings $15,000 for directing inappropriate language toward a referee and failing to leave the court in a timely manner after his ejection in the fourth quarter of Friday night’s loss in Boston.