Talk in the build-up to the Barclays Premier League clash at St Mary's revolved around reports of a mass brawl at the Black Cats' hotel.
Hampshire Police confirmed they had attended the Solent Hotel and Spa in Whiteley, near Fareham, just after midnight in response to a report of assault.
Di Canio revealed the altercation occurred between his staff and three drunk Saints fans after a wedding party, which came just hours before his side's 1-1 draw on the south coast.
"We have to clarify because I don't want speculation, big headlines," the Italian said. "Paolo Di Canio always says the truth so you write what I am telling you.
"At midnight, we walked out from a meeting room with my staff together. From the first floor we walked downstairs to take the lift to go to the third floor for bed.
"Obviously the players went to bed at 10 o'clock or 9.30pm - they were already sleeping.
"Once we were close to the lift, we heard loud people shouting. I can't repeat any of it.
"Obviously their behaviour showed they were Southampton fans, but, to be honest, I don't think they wanted to attack us physically.
"They were only three young, drunk guys there after a wedding party that was inside the hotel.
"Once we walked inside the lift they arrived in front of the lift and started recording with their mobile phone.
"I was screaming from behind the staff and we tried to push the third floor button and they tried to stop and kept going.
"At that moment, they weren't really aggressive but we said 'stop, we must go now, let us go'.
"We tried to say stop and push them away and they started to open the door so we said 'now we call the police'.
"They didn't try to punch us in a clear way but they moved their hands and we stopped them, blocked them.
"I asked for the police because it wasn't fair that people inside the hotel attack, verbally and physically, members of my staff. It wasn't fair.
"We gave our version and the policeman, at 1.30am, knocked on my door again. I don't know if he loved me.
"He asked me to tell him my version and I said 'listen, I don't have any problem because to be honest they are only young, they're drunk'.
"It was a stupid moment from silly guys under effect of lots of alcohol.
"At the end, there was a fun a moment. They said 'we are going to win, Rickie Lambert is going to score' and Fabrizio (Piccareta, Sunderland assistant manager) said 'no, tomorrow we're going to win'. It finished like this.
"No footballers, no fight. This is the real situation and the way it happened."