HARRISON, N.J. -- Dome Torrent believes the referee "100 percent" made a mistake that cost New York City FC in Sunday's 2-1 Hudson River Derby loss to the New York Red Bulls.

A 60th-minute header by midfielder Daniel Royer gave the Red Bulls the match-winning lead, but it was a controversial non-call in the build-up to the goal that proved to be the match's main talking point.

In the preceding play, NYCFC thought they had conceded a corner, a point backed up by the linesman pointing with his flag to signal as such. Instead, the Red Bulls took a quick throw-in -- catching NYCFC, who were setting up for a corner, in limbo -- and Cristian Casseres Jr. crossed into the box where Royer headed it beyond goalkeeper Sean Johnson.

The right call was in fact a throw-in, but referee Alan Kelly never signalled that he was overriding the linesman's call. NYCFC head coach Torrent told Kelly that the lack of a clear signal was the deciding factor in his team's loss at Red Bull Arena.

"I say: 'You make a mistake and you know that.' He know that, he know that 100 percent," Torrent said after the match.

"You have to review on the TV if you don't. It's clear. It's not just one second, it's three seconds."

NYCFC captain Alex Ring backed up Torrent's comments, before accusing referee Kelly of being "part of the Red Bull team."

"It's just a shame to lose the points because I think the referee had a horrible game today," Ring said.

"He doesn't say anything, he just let the play continue as if he is part of the Red Bull team.

"I think it is just common decency. If it's that clear, the linesman shows to the corner flag -- I agree that it is a throw-in because I saw it the same way and then you let everyone know.

"I talked with a couple of Red Bull players who were surprised as well. I think we have to speak about this because it is not the first time we've had games go against us because of the referee."

What happened after the goal was organized chaos around Kelly, with nearly every NYCFC player on the field surrounding him angrily for several minutes. The protests continued after the match, with players and the staff arguing as Kelly walked off the field and through the tunnel at Red Bull Arena.

Alex Muyl, who made the quick decision to take a throw-in, didn't see the linesman signal a corner kick. He also didn't see any indication from Kelly that it was a throw-in or any other call. He just threw the ball in.

"For me, it was clearly a throw-in, that's why I threw it in," Muyl told ESPN FC. "If I had seen him put a corner, I would have gotten ready for a corner."