New York ? In an unscheduled preliminary to Saturday night’s heavyweight championship fight in Los Angeles, three spurned autograph seekers took on Mike Tyson in a Brooklyn hotel lobby early Saturday morning. Big mistake — everybody lost.

Police said the former heavyweight champ was standing in the lobby of the Marriott Hotel at 360 Adams St. at 5:30 a.m., waiting with his sister for a ride to a local airport to catch a connecting flight to the Lennox Lewis-Vitali Klitschko title fight in Los Angeles.

Just then, two men and a woman from Reading, Pa., returned to the hotel, drunk, after a night on the town, a police official said. When they asked the ex-champ for his autograph, Tyson refused and took an escalator up one level. The three from Pennsylvania followed, badgering Tyson for the autograph, a source said.

“There is a verbal exchange,” said the official. “One of the males (later identified as Samuel Velez, 22, 5-feet-4, 245 pounds) makes overtures that he has a gun. Tyson knocks him out.

“The other male (identified as Nestor Alvarez-Ramos, 24, 5-feet-8, 160 pounds) picks up an object from the hotel lobby (a stanchion that holds a velvet rope) and swings it at Tyson. He misses. A melee ensues. The woman (identified as Thamara Ocasio, 27, the wife of Velez) jumps in.”

In an instant, the 36-year-old champ — 5-feet-8, 230 pounds — and the two men are rolling around on the floor of the hotel lobby, flailing away at one another.

Hotel security called the cops and when police arrived, Tyson submitted meekly to handcuffs, telling one officer, “OK, I don’t want any trouble.”

Later, when he was placed in a holding cell at the 84th Precinct, he “behaved like a gentleman,” one official said.

Velez and his wife suffered bumps and bruises. Velez was treated at Long Island College Hospital and his wife at Bellevue Hospital.

Tyson suffered minor scratches to his right hand. Tyson and Alvarez-Ramos were taken to the 84th Precinct station. At 4:30 p.m., Tyson was released on his own recognizance on a third-degree assault charge. Alvarez-Ramos, complaining of severe pain, was taken from the station in handcuffs to Long Island Hospital, where he was reported in stable condition. Both Alvarez-Ramos and Velez were awaiting booking for disorderly conduct and menacing; neither was released because they are from out of state and one has an outstanding warrant.