Ishtpal Singh, 32, stared straight ahead as a Victorian Supreme Court jury delivered their verdict on Tuesday while members sitting in the public gallery wiped away tears.
Jurors had been told Singh was driven by grievances when he "carefully planned" the murder of his friend, Anmoral Singh Bajwa, in January 2025.
But the defence argued he was severely mentally ill and was unable to appreciate the wrongfulness of his actions.
Singh had picked up Mr Bajwa on the evening of January 20 when they went to buy food and alcohol for a barbecue at Shillings Park, near the victim's home in southwest Melbourne.
Unbeknownst to his friend, Singh had earlier that day scoped out the park in Mambourin and hid a metal pole in shrubbery, prosecutor Jim Shaw told jurors.
After the pair ate and drank for more than four hours, security footage captured Mr Bajwa on a video call while Singh relocated the metal pole closer to where they were sitting.
Just after midnight, 17 metal clangs - one after another - echoed through the empty park as Singh used the metal pole to brutally bash his friend in the head and face.
Mr Bajwa suffered catastrophic head injuries and died at the scene.
Singh then drove to Echuca to see his ex-wife before handing himself in to police.
On the way there, Mr Shaw said he called two friends and told them he had hit Mr Bajwa after the victim would not stop taunting him.
Months before the friends' last meeting, their mutual friends were wrapped up in a commercial dispute over the break-up of a transport company, Mr Shaw told the jury.
Singh, who was not a party to the dispute, decided to get involved and took issue when Mr Bajwa opted to "stay out of it".
Meanwhile, the pair had decided to buy a truck for Singh's brother to work with, agreeing to pay half each.
But when Singh went to collect the truck, he discovered he needed to pay an extra $5000 - a commission to Mr Bajwa's friend who assisted with the deal.
This left him feeling angry and ripped off, the Crown told the jury.
"The accused felt his friend had let him down not once, but twice," he said.
Singh also blamed Mr Bajwa for his permanent residency visa being revoked.
Defence barrister Tim Marsh conceded at the start of the trial his client had assaulted his friend, but only intended to harm him.
What he contended was the issue was Singh's state of mind.
"He had a mental impairment present that had the effect of making him not understand that his conduct was wrong," Mr Marsh told the jury.
Referring to evidence from psychiatrist Rajan Darjee, the defence said Singh had been "seriously mentally unwell" for two to three years with paranoid psychosis.
That boiled down to delusions that people were out to get him, Mr Marsh said.
"Those were focused on people he knew, whom he believed were conspiring to ruin his life," he said.
That was rejected by jurors, finding Singh guilty on Tuesday afternoon.
Singh will be sentenced at a later date.
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