Police are investigating a clash at a Celtic Champions League match last night in which a fan ran on to the pitch and apparently assaulted the opposing team's goalkeeper.
The fan managed to get onto the Celtic Park pitch after Scott McDonald had scored a late winner for the home side against AC Milan and was seen to run across the path of Milan's Brazilian custodian Dida before striking him.
Dida appeared to chase after the assailant as he ran away, but then collapsed and was taken away on a stretcher.
A Strathclyde Police spokesman confirmed: "An incident occurred during the match. Police are investigating but nobody has been detained at present."
Celtic said it would carry out a full investigation into the incident.
The incident marred what was a wonderful night for the Glasgow side, who defeated the reigning European champions 2-1.
Two seasons ago Dida was hit by a flare during the Champions League quarter-final between bitter rivals AC Milan and Inter Milan.
Celtic manager Gordon Strachan refused to talk about the incident after the match.
He said: " I'm only going to discuss the football, and on that score it's a great night for us, having beaten the champions of Europe."