Jayson Tatum’s father knew what was wrong during the Celtics star’s recent shooting slump

Over the last two games, Jayson Tatum has made 16 of 28 3-pointers and averaged 43.5 points, 7 rebounds, and 6.5 assists in dominant wins over the Wizards and Kings.Jim Davis/Globe Staff

Celtics star Jayson Tatum’s father, Justin, still coaches basketball at Christian Brothers College High School in St. Louis, so sometimes his schedule keeps him from watching his son’s games live.

But before he looks for box scores or sends texts to his son about his play, Justin always watches a recording of the game first. Last week, as Jayson missed 20 3-pointers in a row while scuffling through his worst stretch of long-distance shooting, it did not take Justin long to see what was wrong.

Jayson’s form looked fine. He was mostly in rhythm. He was usually open. But he was overthinking.

“I said, ‘I don’t know what it is, whether off-court stuff or the team losing, but get out of your own head,’ ” Justin Tatum said by telephone Thursday night. “Sometimes he gets in his own head and if he doesn’t hit shots, he thinks about it more.

“So just let it go, get back to what your natural grooves are and get it done. He’d never missed 20 3-pointers in a row. He’s never shot that poorly for that many games. So just get back to who you are. It’s a quick fix. And it just takes that instant where that light flashes on to where he knows, ‘I’m built for this. This is what I do. Let me get back on track.’ ”

Should Jayson Tatum thank his father for the recent turnaround in his three-point skills?Barry Chin/Globe Staff

Over the last two games, Tatum has made 16 of 28 3-pointers and averaged 43.5 points, 7 rebounds, and 6.5 assists in dominant wins over the Wizards and Kings.

“Once he sees one shot go in, it’s over after that,” Justin Tatum said. “When he hit his first one in that 51-point game [against Washington], I texted someone and said, ‘Yeah, we’re going to see it now.’ I didn’t think 51, but I knew he was going to do his thing. It’s not hard for him to get out of a funk.”

Jayson said this week that his shooting slump might have been a blessing in disguise because it forced him to score in other ways. Justin said Thursday that his son is attacking the basket with poise and purpose, whereas earlier in his career he was sometimes preoccupied with drawing fouls.

“He’s embracing the contact but not looking for it,” Justin Tatum said. “When he looks for it, sometimes he loses the ball or gets distracted and has a turnover. Now he’s going like the contact is supposed to be there, and he’s not reaching his elbows out or doing anything to initiate it. He’s just going through it.”

Jayson has essentially had a year and a half as the team’s undisputed No. 1 scoring option, and the Celtics have gone 61-60 over that time. Last season, they were knocked out of the playoffs in the first round by the Nets, and this season they are once again positioned to be in the play-in tournament.

Jayson Tatum said last week that after reaching the conference finals twice in his first three seasons, he assumed that would be an annual occurrence. He’s since realized the magnitude of the challenge.

But Justin Tatum is thankful that Jayson had those first three seasons to learn from players such as Al Horford, Kyrie Irving, Gordon Hayward, and Kemba Walker. He pointed out that most top draft picks start their careers on bad teams and are instantly thrust into the spotlight.

Over the last two games, Jayson Tatum has made 16 of 28 3-pointers and averaged 43.5 points.Nick Wass/Associated Press

“I’m glad all of this came onto his shoulders during his fifth year rather than his first,” Justin said. “Now he’s matured and had superstars around him, had success, and now when he has to carry the load he’s mature enough and ready to do it.”

Jayson Tatum first dealt with outsized expectations during his sophomore year at Chaminade High School in St. Louis. But that team was upset in the district tournament. Then as a junior he emerged as the No. 1 recruit in his class, and as a senior he led Chaminade to a state title.

“He was down on himself for a while at the end of his sophomore year and trying to figure out why he couldn’t get over the hump,” Justin Tatum said. “Then he had one of the best summers of his young career. You’ve got to have a short memory. That’s all I’ve ever really preached to him. As long as you have another game to prove yourself, let’s get it done.”