Wegener, 34, has pleaded not guilty to murder in the Brisbane Supreme Court after Mr Suttie was stabbed in the neck by a "scalpel-like" weapon south of Brisbane in August 2018.
Mr Suttie, 37, died three days after a major artery was severed by an extremely sharp implement in a late night altercation between two groups at Prince Park, Woodridge, the court heard.
The Crown alleges Wegener may have had a "degree of animosity" toward Mr Suttie after an incident years earlier that occurred when they lived in the same Logan caravan park.
At the time Mr Suttie confronted a 13-year-old Wegener who he believed was threatening a boy and put him in a headlock.
The teenage Wegener then produced a knife, waving it around before stabbing Mr Suttie in the thigh.
"There's no dispute that happened," crown prosecutor Greg Cummings told the jury on Tuesday.
Wegener also told his girlfriend days after the Prince Park incident that he had stabbed Mr Suttie when he was younger because he had "touched him", the Crown alleges.
"You may ... reach the conclusion that there was a degree of animosity held by the accused towards Ben and that might provide motive for him to be violent towards him," Mr Cummings told the jury.
But he said the childhood incident was only relevant if the jury found that Wegener recognised Mr Suttie in the "very dark" park before his neck was cut in 2018.
The Crown alleges Wegener and Mr Suttie's respective groups met by chance at about 11pm in the park four years ago.
An intoxicated Mr Suttie was returning from a night out with three others including his 19-year-old son when they passed Wegener's five-strong group that included two children aged four and eight, the court heard.
The Crown alleges Wegener picked a fight after an unarmed Mr Suttie said "how are you going guys" to the other group as he passed by.
In the ensuing scuffle Wegener produced the weapon from a satchel and targeted Mr Suttie's throat, Mr Cummings said.
Wegener fled after the alleged attack which left blood spurting from Mr Suttie's throat, the court heard.
The weapon has never been found.
Mr Suttie's carotid artery was severed by a scalpel-like sharp object that produced an extremely clean cut, Mr Cummings said.
He said it was so clean that when medical staff rejoined the artery they simply sewed it back together without preparing either end which was extremely rare.
However, Mr Suttie's life support was turned off days later after multiple organ failure caused by severe blood loss.
The trial before Justice Melanie Hindman continues.
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