Former Knicks coach Jeff Van Gundy went on a radio rampage Thursday in the wake of his buddy Tom Thibodeau getting axed by the Bulls after a well-documented rift with management.

Van Gundy said Bulls management engaged in a “downright vicious’’ campaign against Thibodeau, making the organization look “unbecoming” and stating a “pattern’’ exists dating to Phil Jackson’s run as coach. He also called media coverage in Chicago on the issue “repulsive.’’

Thibodeau was Van Gundy’s assistant coach with the Knicks and Rockets. Thibodeau landed his first head-coaching job in Chicago five years ago and posted a 255-139 record (.647 winning percentage), making the playoffs each season.

“I look back at the pattern,’’ Van Gundy said on Stephen A. Smith’s SiriusXM show. “It’s his first head-coaching job. He has no pattern of friction with anybody. The pattern of friction comes from the Bulls side. There’s a long history [in Chicago] of contentious management/coaching relationships and this turned out no different.

“When you coach five years in one place, you have really done a great job of getting a lot of time in. Very few get to five years. It’s not the firing, it’s all the stuff that leads up to a change in direction they want. It’s unbecoming to try to uplift yourself by diminishing someone else.

“Hopefully they’ll treat their next coach better,’’ Van Gundy said, adding he expects Iowa State’s Fred Hoiberg to be hired.

The Bulls released a statement Thursday in which general manager Gar Forman said “a change in approach’’ was needed. Owner Jerry Reinsdorf cited a breakdown in relations between coach and management. During a press conference Thursday, Bulls management said it had expected a better performance in Chicago’s second-round playoff loss to the Cavaliers given the injuries that had depleted the Cleveland roster. The Cavaliers dispatched the Bulls in six games.

“This is not Hollywood, this is the NBA,’’ Van Gundy railed. “Bad people have been doing bad things to good people for a long time. Unfortunately, in this situation it impacted a great person and a great coach.’’

Even President Obama, a Bulls fan, expressed regret about the firing of Thibodeau — regarded as arguably the NBA’s best defensive coach, whose stint was hampered by knee injuries to Derrick Rose.

“He can walk away really proud of what he accomplished and how he conducted himself,’’ Van Gundy said. “He never got down in the muck. He never went off the record trying to hurt them like they tried to hurt him.’’

In that regard, Van Gundy added, “So many in the Chicago media [were on] a one-sided smear campaign to try to diminish Tom’s accomplishments. I found it really repulsive.’’

Van Gundy has interviewed for the head-coaching vacancy with the Pelicans, who reportedly also have interest in Thibodeau. Van Gundy declined comment to The Post on the New Orleans situation.

After a 17-65 campaign, Knicks coach Derek Fisher is expected to get at least one more year to prove himself, but it’s not too wild to imagine Jackson having interest in Thibodeau if he still is available next summer or if Jackson is no longer around.