Finally, Doc Rivers has an NBA championship.

He got it Tuesday night as coach of the Boston Celtics, who in 1988 thwarted his best chance as a player with the Atlanta Hawks.

Rivers was an All-Star that year and a legitimate sidekick to Hall of Famer Dominique Wilkins, and Rivers was at the top of his game in the sixth game of the Eastern Conference semifinals. He scored 32 points that May 20 night.

But the Celtics squeaked by in Atlanta’s Omni, 102-100, with the Hawks’ Cliff Levingston — not Wilkins or Rivers — winding up with the ball for what turned out to be a forced last-second shot.

That sent the series back to Boston for the deciding game, which featured a fabulous fourth-quarter shootout between Wilkins and Larry Bird but wound up as another Celtics win.

I covered that sixth game in Atlanta and had other chances to deal with Doc — after games, in training camp and in a couple of one-on-one opportunities when he visited our area. I watched him give a full-out mini-clinic, not just a token appearance, one afternoon at a Lee College camp, long before the Cleveland school was a 4,000-student university, and I saw how the young players responded to his attention to them.

Rivers was exceptionally dedicated to community involvement and extremely accommodating to reporters — beat writers and occasional interviewers alike.

The Pro Basketball Writers Association honored him with their J. Walter Kennedy Citizenship Award in 1990, and no one was surprised when Rivers went straight to a television job after his 13-year NBA playing career. Few were surprised to see someone give him a shot at coaching.

Describing Doc as a “true leader,” Orlando Magic general manager John Gabriel said in announcing him as the franchise’s fifth head coach in June 1999: “He has a very magnetic personality and a sharp basketball mind.”

Rivers did so well quickly improving the Magic that he was voted NBA Coach of the Year for going 41-41 that first year, and he followed that with seasons of 43-39, 44-38 and 42-40 before things went sour and he was fired after a 1-10 start in 2003-04. He went to Boston the next year and was 45-37, but then came 33-49 and 24-58 seasons with Paul Pierce and little else to work with.

By then some of the media had joined a host of bloggers and fans in turning on Doc. Oh, they still liked him, but they questioned his coaching ability. More than a few suggested that Danny Ainge, the Celtics’ head of basketball operations, had wasted his high-profile acquisitions of Kevin Garnett and Ray Allen this past offseason by not bringing in another coach to mesh them with Pierce.

Boston certainly should be a contender for best in the East, most agreed, but even if the Celtics won their conference, all the powers and coaching wisdom in the West would keep them from an overall championship. None of the Big Three had ever won one, after all, and their coach hadn’t been close.

Even as Rivers directed the Celtics to the league’s best regular-season record, 66-16, there were skeptics. As they struggled to put away the Hawks and the Cleveland Cavaliers in the playoffs’ first two rounds, the criticism grew again. The Pistons would take care of Boston, some were certain. Then the Lakers for sure.

But the Celtics beat both in six games, making a spectacular comeback to win Game 4 of the finals in Los Angeles. And they left no doubt by halftime in their 39-point crowning triumph, which officially ended about seven minutes before Rivers could have said “Happy Birthday” to his father if Grady Rivers had not died as the season was getting under way.

It has been well documented how much Doc’s dad meant to him, and how his father was a model of consistent leadership who continually reminded him that he had to provide a similar example as the Celtics struggled through their awful season last year.

Pierce when Rivers arrived and Allen this year had trouble adjusting to his coaching style, but both came to respect it. I don’t claim expertise for in-depth analysis of coaching, but from afar I saw not only those guys and Garnett blending and picking each other up, but so-called role players playing big parts.

Rivers supposedly couldn’t coach defense last year, yet this Boston team won with fierce defense. And if offense can be talent turned loose in some cases, defense definitely requires coaching and motivation.

But back to that close, close chance for Doc to advance as a player to the Eastern finals in 1988. Twenty-two of the Celtics’ points that night, including the final one, No. 102, were scored by one Danny Ainge.

Ainge owed Doc some extra title help, and now he’s paid up.