Conor Hagan fell to the ground after being struck in the back by the rocket before it exploded.
His team Linfield had just suffered a 2-1 defeat by sectarian rivals Cliftonville in the County Antrim Shield final at Windsor Park in Belfast.
The attack, which sparked riots afterwards, came as players for Cliftonville, a largely Catholic-supported side, had missiles thrown at them by fans of the losing side, which is typically followed by protestants in the divided city.
Hagan, 26, was tended by team medics and members of both sides before being able to regain his feet.
'I was lying on the ground disgusted with the result and didn’t see the firework coming,' he told the Belfast Telegraph.
‘It hit me on the back when it went off and it was more the bang that scared me and I was in shock for few seconds.
‘It could have been a lot worse so I am relieved that I am not injured.’
The attack came as many people in the province - like the rest of the UK – prepared to celebrate Bonfire Night tonight.
Fireworks have been on sale at major supermarkets for weeks in preparation for the event.
Afterwards, police were called to riots between fans of the two sides in the Newtownards Road area of East Belfast.
Linfield manager David Jeffrey said: ‘The last thing that I want to do is inflame the situation.
‘I don’t want to talk about one idiot, but it has got to be condemned outright.’
Cliftonville coach Eddie Patterson, who was the subject of a death threat before the Irish Cup semi-final last season, also condemned the incident.
‘I don’t even want to highlight it that much - it only gives these people publicity. It has no place in football.
‘Some of my own players had missiles thrown at them, but I would rather talk about the Linfield fans who applauded us off the pitch. That’s what football’s about.’
