He’s not so tough now.

Cops have arrested the monster who they say repeatedly kicked a cowering elderly woman in the head aboard a Bronx subway train — as callous straphangers did nothing more than pull out their phones to record the beatdown.

But the suspect, restaurant worker Marc Gomez of Yonkers, is denying he kicked the woman — even as he insists she came at him with a knife.

“She was homeless and lying across the seat and wanted all other passengers to move,” Gomez’ court-appointed lawyer claimed of the 78-year-old victim during an early Sunday Bronx Criminal Court arraignment.

“She said, at that point, ‘I have a knife and I’m going to stab you,’” and flashed “a sharp instrument,” the lawyer, Steven Mechanic, claimed.

Earlier Saturday, a former neighbor of the victim had told The Post the elderly woman was mentally ill — and had threatened residents in the past with a knife.

Gomez 36, was charged with felony assault and ordered held in lieu of $30,000 bail after prosecutors said he has a misdemeanor conviction and an open gun possession in The Bronx.

Gomez had been free without bail on that case since November, when he was stopped on the Cross Bronx Expressway by cops who found a 12-gauge Mossberg shotgun plus ammo in his car, according to law-enforcement sources.

Gomez also has old, sealed arrests for assault and possession of a gun and marijuana, sources said.

Footage of the March 10 violence went viral after it was posted on social media — prompting outrage not only for its brutality, but because at least two straphangers whipped out cellphones to record the incident instead of trying to help.

Investigators with the Bronx Transit Robberies Squad busted him Saturday morning after a tipster who’d seen the bystander cellphone video of the attack recognized him, and called his name in to the Sixth Precinct, sources said.

He was busted in Tribeca, wearing a double-breasted chef’s jacket and a Boston Red Sox baseball cap.

“The defendant was recorded on video kicking a 78-year-old woman on a subway in The Bronx,” prosecutor Theresa Genthe said in asking for the high bail.

“The defendant viciously kicked her six times, while wearing boots, about the head and face.”

Video of the March 10 violence on a northbound 2 train went viral on social media — prompting outrage not only for the brutality but because at least two straphangers whipped out cellphones instead of trying to help.

By Sunday, a clip of the 3 a.m. attack had nearly 13 million views.

In it, the attacker holds on to the pole above her head for balance as he lands his kicks.

The first two blows strike her in the head, which snaps to the side from the impact. Other kicks hit her stomach and left breast.

Warning: Graphic violence and explicit language

She can be seen waving her arm in a futile attempt to block the blows.

A crowd of straphangers can be heard “ooo-ing” and “aww-ing” each time a kick connects, as if cheering at a boxing match.

Another cellphone user, who appears to be only 10 feet away, veers in and out of the foreground of the clip as he angles his screen left and right to get a better view.

The victim, whose name is being withheld by The Post, “is getting care, advocacy & support,” Chief of Detectives Dermot Shea tweeted in announcing Gomez’s apprehension. “The subject wanted for the brutal subway attack of an elderly woman IS IN CUSTODY,” Shea reported.

The victim’s former Bronx neighbors told The Post on Saturday that she is a childless, retired kindergarten teacher who moved out three or four years ago.

“She was just mentally ill,” one woman at the co-op said. “She wasn’t paying rent. She threatened at least three co-opers with a knife… She used to call the fire department, cops all the time.”

Additional reporting by Khristina Narizhnaya, Amanda Woods and Laura Italiano