In New Jersey and immediately encounter crowd trouble ahead of the New York derby (Red Bulls-City). Video: pic.twitter.com/slY3hYn5aM — Rob Harris (@RobHarris) August 9, 2015

The Hudson River derby between the Red Bulls and expansion New York City FC isn’t even a season old, but there’s already plenty of hate. And that hate spilled over into the streets in the form of a brief disturbance, with fans of both teams clashing in Newark before Sunday night’s third and final tilt in the season series.

The incident happened at Bello’s Pub and Grill on Market Street, a gastropub frequented by the Garden State Ultras, one of the three supporters groups in Red Bull Arena’s South Ward. New York City FC fans arrived in or near the pub, and a fracas ensued.

Rob Harris, a UK-based reporter for the Associated Press, shot video of the disturbance out on Market Street. Combatants can be seen swinging pool cues, a sandwich board and filled garbage bags. The crowd dispersed quickly when police arrived.

The management of Bello’s declined comment when contacted by The Post. The Newark Police Department has not yet responded to a request for details. But Kearny native Tony Meola — an original MetroStar, and current soccer commentator — did provide an anecdote on the derby and how heated it’s become.

The three-time World Cup goalkeeper has watched the Hudson River derby grow, and remembers being heckled and yelled at by New York City FC fans in the teams’ second meeting, at Yankee Stadium.

“There’s some real hatred,’’ said Meola. “This isn’t fabricated. Where sometimes in the past I think we fabricated maybe because we had to fabricate some of these rivalries.

“Quick story: My best friend from high school is the head cop here, and he took off today because he said he didn’t want to have to work for his money. He called on the way in and said, ‘We’ve already arrested almost 30 people.’ … The point is, there’s a rivalry now.’’

One the front offices have to watch to keep under wraps. The Red Bulls’ front office had slashed two-thirds of rival New York City FC’s traveling supporters, from their initial 1,500 down to just 500, in hopes of maintaining crowd control and avoiding trouble.

In the first of three meetings this year, NYCFC fans came to Red Bull Arena in strong numbers. But after causing a disturbance on the PATH and being forced off the train en route to Harrison, when they arrived, they violated a number of Red Bull Arena policies, including tossing a flare that landed by Red Bulls keeper Luis Robles and forced a stoppage in play.