A Sydney teenager shot dead during a fight after the State of Origin allegedly screamed "shoot me, shoot me" to a high school acquaintance who is accused of pulling the trigger, a court has heard.

Jed Coates, 18, had been at the Colyton Hotel watching the State of Origin game on Wednesday night, just weeks after celebrating his 18th birthday, when police said he became involved in a dispute with a 21-year-old Matthew Perry.

Jed Coates, 18, died from a single gunshot wound. Credit:Facebook

Mr Perry, a Queensland supporter, is accused of later fatally shooting him in the neck.

Mr Coates was taken to Westmead Hospital but died just before midnight on Wednesday, less than an hour after the shooting in Colyton.