Boston Celtics

Cavaliers coach Ty Lue knew Jayson Tatum long before the 20-year-old was drafted by the Celtics.

In fact, Lue and Tatum are cousins, as Lue and Justin Tatum (Jayson’s father) are cousins on Lue’s grandfather’s side. Which has made Lue’s view of Tatum from within the East all the more interesting leading up to this third-round showdown between Lue’s Cavs and Tatum’s Celtics, set to get underway with Sunday’s Game 1 head-to-head at TD Garden.

“Just seeing Little Jay when he was 6 or 7 years old and now to who he is today is crazy,” Lue told ESPN. “Seeing the player he’s become, we knew he was going to be good, but now he’s at a whole new level. Just seeing him coming to Mexico and just coming to my barbecues and all that stuff and now he’s an NBA player and playing at a high level, it’s just good to see.”

Tatum has been a playoff revelation for the injury-depleted Celtics, with 18.8 points and 4.5 rebounds per game this postseason. He helped deliver the knockout blow to the Sixers in round two with a Celtics-best 25 points in Game 5, and also ranks in the top five for clutch scoring this postseason, with 21 points and a 57.1 field goal percentage in clutch moments.

“He’s not scared, he’s not afraid and he’s always been that type of kid,” Lue said of Tatum. “He wants these type of moments and he’s taking advantage of it. With Kyrie [Irving] and Gordon [Hayward] going down and him having a chance to play the minutes he’s been playing, starting and playing in the playoffs the way he has, he’s taken full advantage of it.

“But he’s never been scared, he’s never been afraid of the big moment. You can see that.”

It’s only part of why Lue sees a little bit of C’s legend Paul Pierce, a comparison that’s been made countless times, in Tatum.

“As a little kid he was fast, but I think as he got taller it slowed him down a little bit,” said Lue. “I think that has helped his game a lot. He’s never in a rush, he plays patiently and reminds me a lot of Paul Pierce when Paul first came out. Being able to get to the free throw line, great footwork, never gets sped up offensively so he’s a really good player.”

One that Lue hopes to slow down beginning this Sunday.

Even if it makes for some awkward future barbecues.