A law firm representing a man who was sucker punched after a hockey game at Madison Square Garden — with video of the clash going viral — has become the latest firm to sue the arena over its ban of lawyers whose clients have MSG gripes.

The five lawyers of Greenberg Law PC claim an MSG attorney told them on Nov. 28 – the same day they filed a lawsuit on behalf of punch victim Joseph Urciuoli — they are now barred from entering any MSG-owned venues, according to a Manhattan Supreme Court lawsuit Thursday.

Two of the firm’s lawyers — Alan Greenberg and Joseph DePaola — have tickets to upcoming MSG venue events that they’re no longer allowed to attend.

DePaola has tickets to see the Christmas Spectacular at Radio City Music Hall with his wife and kids, ages 7 and 5, on Sunday and Greenberg has tickets to see comedian Jerry Seinfeld at the Beacon Theater Dec. 17, the filing alleges.

Greenberg Law P.C.

Greenberg Law P.C.

MSG’s ban has essentially “accused” the firm of “unethical behavior without any evidence” that will damage their reputation. And the ban will “intimidate and dissuade potential clients from contacting [the firm] to pursue potential litigation against MSG, its events or venues,” the suit claims.

Greenberg law wants a judge to overturn the prohibition.

“MSG’s position about the ethical implications of an attorney appearing at one of their venues is completely misguided,” DePaola told The Post. “There is no support for the position, no evidence that anybody is going to go up to a bartender or a hotdog vendor and start asking questions about ongoing litigation because we are there for some unrelated event.”

DePaola said he’s disappointed he can’t attend the Christmas show with his family.

“Living in Manhattan — we have two young kids — we try to take advantage of everything the city has to offer and it’s obviously tremendously disappointing,” DePaola said. “It’s not a happy feeling by any stretch to have your kids and your wife pay the penalty for what is a very unfair policy.”

It is at least the fourth law firm to be barred from MSG this year due to ongoing litigation with the historic sports arena.

One of the firms, Davidoff Hutcher & Citron, filed suit in October to nullify the embargo of its 60 lawyers. That case is still ongoing, but courts in that case have issued temporary rulings that the lawyers cannot enter the stadium, while allowing them to go to other MSG venues.

Greenberg law is representing Urciuoli, who lives in Connecticut, in his case against the stadium and James Anastasio, 29, of Staten Island, who slugged Urciuoli and a man wearing a Tampa Bay Lighting jersey as he was leaving a New York Rangers game.

The incident was caught on a video and went viral.

Anastasio socked Urciuoli for trying to stop him from running away after the initial sucker punch.

Christopher Sadowski

Twitter/Scott Kaplan

Anastasio pleaded guilty in September to assault and was sentenced to anger management.

Urciuoli in his suit accused MSG of negligence for having inadequate security and allowing Anastasio to become drunk.

Anastasio’s lawyer, Jason Goldman, previously told The Post his client learned from the incident and called the suit “a last-ditch, money-grab effort against the Garden.”

A spokesperson with MSG Entertainment told The Post: “We expect this particular suit to be over soon and look forward to welcoming back the attorneys from Greenberg Law P.C.”