The parish priest, who suffered two wounds to his head, said that he had no idea why the attacker carried out the assaults.
Speaking at his home today, he said: "It happened when I was saying a few prayers after the 9am mass in the church. I saw a man walk up onto the altar. He went to the tabernacle and took out the ciboriums. I went up and asked him what he was doing and that's when he hit me with them.
"I ran away through the church. I was shocked at what happened," he continued.
The priest said the attacker seemed to be aged in his fifties and that he "may have been deranged".
Officers have identified the suspect who has not yet been arrested.
The attacker also assaulted the sacristan Michael Dillon. He used the ciboriums -- metal bowls used to contain the Eucharist -- as weapons.
He inflicted a serious eye injury on the sacristan in the attack.
The man made a second attempt to attack Fr McManus when the priest was forced to flee the church. The priest managed to close a door with glass panels in the church behind him as his attacker smashed the glass panel while wielding the ciboriums.
The drama was astonishingly captured on camera as part of the parish's new internet broadcasting service.
Masses are streamed on the internet and former parishioners as far away as Canada have been able to watch religious services.
Fr McManus said the gardai were due to arrive today at the church to examine the possibility of retrieving the images from the system.
Mr Dillon is understood to have undergone surgery for his eye injury last night and was still in hospital today.
Both victims were taken to the Mater Hospital. "I'm just relieved that Michael appears to be okay now. He was sitting up in bed last night in hospital," said Fr McManus.
The priest shrugged off his own injuries and made light of the two scars on the side of his head. "I'm okay, I've got a hard head," he said.
Fr McManus said that the man fled from the church on foot and several people in the church had phoned the gardai on their mobile phones. Parishioners said later they believed the man was arrested by gardai in the Conquer Hill area of the northside.
Local parishioner Andy Jackson (79) said: "Everyone is very shocked by what happened. Father Pat is one of the best. Everybody loves him. He's a gentleman. We heard the sacristan got the worst of it. We just hope they get better soon."
The parish priest said he was enormously heartened by the messages of support he has received. Among the messages was a goodwill message from local Church of Ireland minister Robert Deane.