Graham Booker, 68, flew at retired policeman Richard Hadley like "a mad bull" during the assault in Sidmouth, Devon, last October, magistrates heard.
It happened after Booker saw Mr Hadley in an alleyway between Sidmouth Methodist Church and his home.
Booker was convicted of assault after a trial at Exeter Magistrates' Court.
The court heard how Mr Hadley had been using a wrench to remove some nuts from a metal gate in the alleyway, when Booker came out of the church's fire exit.
Mr Hadley said Booker raced towards him, shoved him to the ground and kicked him.
He said: "I went sprawling on the floor. My nose hit the ground. It was streaming blood. I lost a tooth. I must have been knocked out for a few seconds. Booker was standing over me and kicked me."
The victim, who owns the Hair Studio next to the church, said he had the right to use the alleyway to access the rear of the property, which the church disputes.
Mr Hadley said he had had used the alleyway for 30 years and it was the only way into his "landlocked" property.
In court he branded the church an "absolute disgrace".
Booker, of Windsor Mead, Sidmouth, claimed he did not kick Mr Hadley but was kicking away the wrench and said he had acted in self defence.
He was released on bail and will be sentenced at a later date.
A spokesman for Sidmouth Methodist Church said: "We are deeply saddened by the situation and hope that all those concerned can soon put this unfortunate matter behind them and move forward in reconciling relationships within the community."
A church steward attacked an 85-year-old neighbour in a row over a disputed alleyway, knocking him to ground and leaving him with a missing tooth.