Justice Selwyn Selikowitz rejected Morne Langeveld's defence that his rage resulted in non-pathological criminal incapacity, which translates into temporary insanity.
Langeveld, 24, strangled Johannes Theunissen at the latter's Goodwood home on July 28, 1999.
Langeveld had twice spurned Theunissen's sexual advances whereupon Theunissen had sworn at him.
Langeveld, who only a year before had lost his mother from cancer, and had a very close relationship with her, claimed that the insult had enraged him.
Langeveld, who removed items from the house, including sound equipment, was also found guilty of robbery.
Langeveld's fianceeé as well as his sister were present in court, and wept when the judge withdrew Langeveld's bail and ordered that he remain in custody until sentencing procedures commence on April 23.
The judge said it was not in the interests of justice for Langeveld's bail to be extended considering evidence of his suicidal tendencies.
The judge said he found it difficult to accept that a single insult would have triggered the incident that followed.
He said experience had shown that where people lose control of themselves they act chaotically, in a frenzy, fire a gun until there are no more bullets, or continue to stab a victim until exhaustion ends the attack.
The judge said: "In this case we have a calculated systematic multi-step consecutive set of actions, each of which required the accused to evaluate the situation before proceeding to the next step."
The judge said the probabilities were that Langeveld had needed money to pay off a second-hand motorcycle to get to a job that he was starting soon.
Langeveld had then gone to a house that Theunissen shared with others, and had seen Theunissen's sexual advances to him as an ideal situation in which to rob him of sound equipment and other items in order to obtain money to pay the first instalment for the motorcycle which was due soon.
Langeveld first strangled Theunissen in an arm lock until Theunissen collapsed. Langeveld then grabbed him by the throat as he lay on the floor and again throttled him.
When Theunissen again appeared to recover, Langeveld strangled him with a necktie and pushed his body under a bed to make it appear as if there had been a burglary. - Sapa