If you missed it ... Harrell went viral Friday for his trash talk of the Dallas point guard -- when cameras caught the L.A. player mouthing the words to Luka after a big first-quarter bucket.

Of course, given the nation's current climate and battle for racial equality ... Montrezl was heavily criticized for the chatter -- with ex-NBA player Jay Williams saying straight-up, "I can only imagine if Luka Doncic had said something like that to you."

Montrezl says he took it upon himself to clear the air with Luka before Game 4 on Sunday ... and in video of their conversation, you can see there was no bad blood at all.

"Nothing but respect for Luka," Harrell said of their pregame embrace. "He understood the heat of the battle and he said it didn’t bother him only RESPECT."

For his part, Luka said he accepted Harrell's apology ... adding, "No worries."

"There’s a lot of emotions on the court, especially this is playoffs," Doncic said. "Sometimes you say things you don’t want to say. He apologized. I respect that, so no problems.”

Clippers coach Doc Rivers says he addressed everything with Harrell in house ... telling reporters over the weekend that Montrezl MUST be more careful with his words.

"I said to him, ‘Hey, I don’t think you meant anything racially by it.’ He said ‘white boy,’ but I don’t think there was anything racial intended," Rivers said. "But we are in a very heightened climate and you have to be careful."