The fired computer repair store worker who shot his former boss in a broad-daylight Upper West Side attack was busted Friday morning — nearly 24 hours after he escaped through subway tunnels and even hid out under a train, law enforcement sources said. 

Eduardo Diaz, 42, of Queens, was picked up on a warrant and charged with attempted murder, assault and weapon possession in connection to the Thursday morning shooting that wounded Boris Shapiro, 47, at West 69th Street and Columbus Avenue, the sources said. 

“I heard,” Shapiro told The Post of Diaz’s arrest when reached by phone Friday at Mount Sinai Morningside, where he was recovering. “I feel great. I was nervous that he’d come back again.”

The two men worked together at the nearby Lincoln Business Machines Incorporated, sources said — and Diaz had been fired months before the shooting, the victim told PIX 11 Thursday night.

“I’m stable. I should be fine,” Shapiro told the outlet. “[The gunman] got fired six months or a year ago.”

Diaz showed up at his former workplace about a block away from the scene shortly before the shooting, but left without hurting anyone, the victim told the outlet. 

But Shapiro, fearing his ex-employee was capable of worse, followed the menace up Columbus Avenue. 

“I wanted to call the police,” he told the network. “He came in [the shop] with a gun and I was afraid he would come back and trap us, so I called 911. And that’s when he saw me and ran after me.”

That’s when the irate gunman blasted Shapiro once in the shoulder and once in the leg out on the street around 9:20 a.m., police said.

The shooter then fled into the 72nd Street train station, where he crept under an A train in the tunnel – and somehow managed to continue his  escape bid, sources said. 

The runaway gunman wreaked havoc on some straphangers’ commutes – with many forced to lie on the subway floor and then evacuate through the subway tunnel. 

A woman who lives above the computer shop said she watched as tensions boiled over between the shooter – who apparently worked remotely – and his employer. 

“They started arguing inside the store and then right out here, yes, in front of the store. And then all the way down to the corner,” she said. 

“He was working remotely, doing some service for the computer company,” the neighbor said. “There apparently was some kind of a problem over money. I can’t remember exactly what he was screaming but it was something about money and something about being cheated or wronged … It was terrifying.

Birgilio Rojas, 56, who owns Traviata Pizza next door, said he saw the victim regularly for “many, many years.”

“Sometimes I need a copy or something made and he gives it to me and he comes here for the slices,” Rojas said. “[He’s] a nice guy, you know, he’s part of the neighborhood.”

Maya Shatsky, 25, who lives around the corner from the shooting scene, said she was getting ready for work when she heard the shots ring out.

Shatsky said she and her roommate – who both grew up on the “family-oriented Upper West Side” – are troubled by the unexpected violence.

“We’re just shocked,” she said. “Like something like that doesn’t just happen outside of our doorstop, maybe in like Times Square, somewhere like that. But not at 69th and Columbus at 9:30, 9 a.m.”

“We feel generally very safe, still,” Shatsky acknowledged. “We love the Upper West Side, and I don’t actually know how that happened and what happened outside there. We were just shocked.”