A fight erupted between the 235-pound Barnes and Fisher, who weighs in at 200 pounds.
Cops were called to the scene, but Fisher, 41, left before the law arrived and won’t be pressing charges, sources said.
Following the dust-up, Barnes, 35, texted a pal that he had not only assaulted Fisher, but also took revenge on Govan, one source said.
“I kicked his ass from the backyard to the front room, and spit in her face,” the text read, according to the source.
A source close to Fisher confirmed the fight, but insisted it wasn’t as one-sided as Barnes claimed.
“Matt came after Derek but he only had a few scratches,” the source said. “Derek’s not going to press charges, he’s going to let it go.”
Indded, Fisher, who declined to comment in detail about the dustup, looked no worse for wear before the Knicks preseason match-up against the Brazilian Paschoalotto/Bauru team at Madison Square Garden Wednesday night.
Govan was planning to file a restraining order against her estranged husband, sources said.
Reps for Barnes and Govan didn’t return requests for comment, but the Grizzlies issued a statement saying it was “aware and currently gathering information regarding” The Post’s online exclusive, revealing the incident.
Asked how he felt in the wake of Saturday’s incident, Fisher 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,” he said.
Fisher also refused to say why he missed the team’s practice on Monday, which the Knicks had tweeted was “due to personal reasons.”
LA court records show Barnes filed for divorce in January, In August, he claimed that he had been dating pop star Rihanna and that they’d gone “past the crush stage” —
but she denied it in an Instagram post that featured hashtags including #thedevilisaliar, #shesneverevenmetyou and #thisactuallyhurtmyfeelings.
Sources said Fisher began dating Govan, 29, “a few months” ago, and on Sept. 27, a Twitter user with the handle @alexiss_henry tweeted: “I spy Derek Fisher with Matt Barnes’ kids.”
In March, Fisher filed for divorce from his wife, Candace, a month after celebrating their 10th anniversary.
Candace, who has twin sons with Derek, responded with court papers saying that she was “blindsided” by the move and discovered that he had secretly moved his stuff out of their New York apartment when she went to check on it, according to TMZ.
Saturday’s violent altercation isn’t the first time that the heavily tattooed Barnes’ anger has erupted.
In 2012, he was arrested for allegedly threatening a California cop who recognized him for an outstanding warrant for driving with a suspended license.
He was also arrested in 2010 on suspicion of felony domestic violence against Govan, who was his fiancee at the time.
She denied that he had abused her during a fight at their home, and the charge was later dropped.
Earlier this year, the NBA fined Barnes $50,000 for directing “inappropriate language at a fan” who was seated courtside during a May 1 playoff game — and who turned out to be the mother of Houston Rockets guard James Harden.
The NBA didn’t detail the trash talk, but reports on Twitter claimed that Barnes, who later apologized, said, “Suck my d- -k, b—h.”
Barnes, who last season played for the LA Clippers, was also fined $25,000 in January for kicking water and cursing at a fan in Washington.
Later that month, he was fined another $25,000 for swearing at Phoenix Suns owner Robert Sarver, who Barnes later said “cussed at me” first.
Barnes met Govan when she was 12, and they started dating in 2006, when he played for the Golden State Warriors.
The couple married in 2012 but split in September.
