Celtic have been fined £42,430 by UEFA after a fan ran on to the pitch during last week's Champions League Group E match against Manchester United at Parkhead.
Part of the fine was imposed for the late start to the game which ended in a 1-1 draw.
UEFA confirmed that "an appeal may be lodged within three days of receipt of the grounds for the decision" but a spokesman for Celtic told PA Sport: "We accept the judgement and there will be no appeal."
The Parkhead club were expecting some level of punishment after UEFA warned them previously about the behaviour of their fans following a similar incident a year ago when a fan confronted AC Milan keeper Dida.
They were then found guilty of a lack of organisation and improper conduct of supporters and were ordered to pay a fine of £25,000, half of which was suspended.
It is not clear how today's fine was calculated but a statement on UEFA's official website read: "Celtic FC have been fined 50,000 euros by UEFA for the improper conduct of their supporters at last week's UEFA Champions League Group E match against Manchester United FC in Glasgow.
"The UEFA Control and Disciplinary Body handed down the fine to the Scottish club in relation to a pitch invasion by a spectator and a late kick-off at the match, which ended in a 1-1 draw.
"An appeal may be lodged within three days of receipt of the grounds for the decision."