The Memphis Grizzlies superstar did it all before a judge in Tennessee ... as part of Joshua Holloway's civil case against him.

Holloway claims in the lawsuit that Morant assaulted him while the two were hoopin' at the NBA player's Shelby County residence in July 2022 ... though Morant and his attorneys say the suit should be dismissed, claiming Ja was simply attempting to protect himself during the incident.

At one point during Monday's proceedings, Morant told Holloway's attorney he was physically "hurt" when the teenager threw a ball at his face during a check situation.

Morant said in the courtroom that he asked Holloway, "What you on?" after the teen heaved the ball -- and then he claimed Holloway pulled up his shorts.

"Him pulling up his shorts," Morant testified, "where I'm from, that's a fighting stance."

Morant claimed Holloway then took a step at him -- and that's when the NBA player fired off a punch.

"I hit him first," Morant said, "to protect myself."

Morant was also seen in the courtroom showing a lawyer how a normal check-ball situation is supposed to go down.

Morant's dad, Tee, spoke as well from the stand during the hearing -- and it's anticipated he'll continue testimony Tuesday.

The proceedings, meanwhile, are slated to go through at least Wednesday -- and if it's ultimately deemed Morant was, indeed, acting in self-defense, the case could be dismissed. However, if it's not, a trial could be slated to begin in April.