After D'Mello denied the claim Patel confronted him again later that day, but this time he was surrounded by a gang of 12 men wielding sticks, bricks and knives and stabbed twice in the chest.
Adnan tried to protect himself with a golf club, Akeel Shah plunged a blade four inches into the victim's chest, Munawwar Patel, another of Adnan's brothers, told the jury.
With brother Imran cowering in the back seat, Patel staggered into his car and tried to drive away but crashed just one road away before tumbling out to the pavement and dying, the jury heard.
D'Mello and two other men were cleared of the charge of murder but found guilty of committing violent disorder.
All four men are to be sentenced next month.