Joseph Lozito, blood pouring from a gaping slash on his head, had a harsh warning for Brooklyn butcher Maksim Gelman after taking him down aboard a packed No. 3 train .

“You better hope I f—ing die, because I’m going to kill you if I don’t,” he screamed as two hero cops subdued the 23-year-old accused killer, who allegedly stabbed three people to death and fatally ran another down during a blood-soaked 28-hour crime spree Friday and Saturday.

MADMAN’S RANT: ‘SHE HAD TO DIE’

STALKER COULDN’T TAKE NO FOR ANSWER

TIMELINE: GELMAN’S 28-HOUR TRAIL OF CARNAGE

Lozito, speaking today from his hospital bed at Bellevue, gave The Post a harrowing account of his brush with death as he came face to face with the drug-addled psycho.

Lozito, a married father of two boys age 7 and 10, said he was sitting on the train on his regular commute from suburban Philadelphia to his box office job at Avery Fisher Hall when Gelman caught his eye.

“I was on the seat right near the door (to the motorman’s compartment). This guy walked by and he looked creepy. He looked shady,” said Lozito, a burly 40-year-old who stands 6-foot-2 and weighs 265.

The suspect tapped on the motorman’s door. Transit cops were inside, and Officer Terrence Howell asked “Who are you? ” recalled Lozito, his wife Andrea by his side.

“He said ‘Police! Police!’ and the cop said ‘No you’re not,’ ” Lozito said. “He’s two or three feet away from me, and he pulls this knife out, looks me in the eye and says ‘You’re gonna die! You’re gonna die!’ And he lunged at me with the knife.”

Gelman swung wildly and stabbed Lozito on the back of the head. As Gelman drew his arm back for what might have been a fatal cut, Lozito saw an opening.

“There was a split second, as soon as I saw his arm go back, I knew it was my chance to move. I tried to take him down with a wrestling move called a single leg takedown, but it ended up more like a football tackle,” Lozito said.

As the pair scuffled, Howell and Officer Tamara Taylor sprang into action, with Howell jumping on Gelman and Taylor grabbing the blood-smeared carving knife, one of six the suspect carried during the violent rampage.

“I was begging everybody, cops and passengers, to get me off the train. I said ‘I got a wife and two kids, I can’t die on this train,’ ” he said.

One passenger applied pressure to his head wound to stanch the flow of blood.

“I owe him a debt of gratitude. To me, he’s the reason I’m alive,” he said.

Despite his wounds, a courageous Lozito said he was glad Gelman targeted him.

“I’m glad he didn’t go after a child, or after a woman, or after an elderly person, because I can defend myself,” he said.

Gelman, who has a lawyer and is not talking to the police, was expected to be arraigned later today. The Brooklyn DA’s office said he would be charged with four counts of second-degree murder, single counts of first-degree and second-degree assault and three counts of counts of first-degree robbery.

Another victim, Arty DiCrescento, told The Post today he’s lucky to be alive, but it was pure bad luck that put him in the Gelman’s path in the middle of his murderous rampage.

“I’m lucky in one sense,” he said today from his hospital bed at Brooklyn’s Lutheran Medical Center. “But in another sense, I never should have been there and it never should have happened.”

An angry DiCrescento, 60, said it was clear to him that the madman who hacked three people to death, fatally mowed down another and stabbed three more was out for blood.

“He’ll probably use the insanity defense but it was premeditated. He went after three people he knew first,” said the burly DiCrescento, his hands and wrists bandaged and a large bruise on his neck.

DiCrescento was double-parked in his Pontiac Bonneville on E. 24th Street in Brooklyn Friday afternoon when Gelman, who’d already allegedly fatally stabbed his stepfather Alexsandry Kuznetsov, 54, a one-time date Yelena Bulchenko, 20, and her mother Anna, 56, pulled one of six kitchen knives he was carrying and stabbed him in the chest.

Gelman then sped off in DiCrescento’s car and mowed down Steve Tannenbaum, 60 , who was crossing Ocean Avenue near Avenue R. Tannenbaum later died at Kings County Hospital.