NBA bad boy Matt Barnes, 35, discovering that New York Knicks coach and former teammate Derek Fisher, 41, was spending time with Barnes’ estranged wife, drove from Santa Barbara to Los Angeles to fight him on Saturday.

Sources told The New York Post that Barnes, 6’7”, 235, left the Memphis Grizzlies’ training camp after his six-year-old twin sons, Carter and Isaiah, called him to tell him Fisher, 6’1” 200, was at the home of Barnes’ wife, Basketball Wives LA star Gloria Govan. One source said, “Barnes went crazy. He got in his car and went to the house and went after Fisher. Matt then drove down there to beat the s–t out of him.”

A source told the Post that Barnes texted, “I kicked his ass from the back yard to the front room, and spit in her face.” But one of Fisher’s friends denied Barnes’ version of events, claiming, “Matt came after Derek, but he only had a few scratches. Derek’s not going to press charges; he’s going to let it go.”

Other sources told the Post that Govan would file a restraining order against Barnes. Barnes filed for divorce from Govan in January; they met in 1998 when she was 12, and married in 2012, according to the Post.

The Post reported that Fisher, who started dating Govan, 29, “a few months” ago, filed for divorce from Candace, his wife of 10 years, in March. Candace Fisher said she was “blindsided” by the divorce and found Fisher had surreptitiously moved his belongings out of their New York apartment when she visited it, according to TMZ.

Fisher missed the Knicks’ team practice on Monday but returned on Tuesday. He said, “My state of mind — like I talked to the guys a few minutes ago — is personal, and private matters are personal and private. I’ve been through a lot in life. Sometimes, we go through things we can’t or can control. I’m here. I’m focused. It’s not something that’s going to take me away from what we’re trying to do.”

Barnes has a history of angry incidents, including his arrest in 2012, for allegedly threatening a California cop, his 2010 arrest on suspicion of felony domestic violence against Govan, his fiancée, and cursing the mom of Houston guard James Harden during a May 1 playoff game, allegedly saying, “Suck my d- -k, bitch.”

Barnes and Fisher played together for the Los Angeles Lakers from 2010-12.