There is no dispute Seyram Kwami Djentuh stabbed Lauie Tagaloa in the neck with scissors he bought minutes earlier for $3.90, a jury has been told.
Djentuh pleaded not guilty in a Brisbane court on Monday to murdering Mr Tagaloa during the July 11, 2022 altercation at Fortitude Valley train station.
Mr Tagaloa died just after 4am from an 11.5cm stab wound inflicted to the left side of his neck by Djentuh "in one swift move", crown prosecutor Elizabeth Kelso said in her opening statement.
"Immediately blood can be seen flowing from that wound onto the floor."
The men were in two groups that encountered each other for the first time after leaving different Fortitude Valley nightclubs about 3am.
CCTV and phone footage that will be shown during the trial captures much of the movements of the men from then until after the stabbing when emergency services were called at 4.07am.
Ms Kelso told the Supreme Court jurors that witnesses would describe Djentuh speaking aggressively, being cheeky and rambling about wanting to fight.
Djentuh and Mr Tagaloa were observed "eyeing each other off", with both seemingly keen on a fight when the groups went separately to buy food, she added.
Ms Kelso said footage showed Djentuh getting a bottle of water before going to the back of a NightOwl store and grabbing orange-handled scissors which he tucked into the back of his white jeans.
When a shop worker told Djentuh he had to pay for the scissors, the defendant said there were guys outside who wanted to stab him, Ms Kelso said.
Djentuh told the worker he wanted to hide the scissors so they could not be seen, but paid for them before leaving the store.
Inside the Fortitude Valley train station a short while later an altercation with yelling and swearing started between the two groups.
Ms Kelso said footage showed some men clenching their fists and an argument or discussion between them.
As some men faced each other you could see Djentuh reaching behind his back to where the scissors were, she said.
Mr Tagaloa grappled with a member of the other group before swinging a punch, Ms Kelso said.
"You'll see Lauie Tagaloa standing over the top of him and throw multiple punches at him and then stomp down towards his head."
One minute and 40 seconds after the men entered the train station, Djentuh swung the scissors in a swift movement into the left side of Mr Tagaloa's neck before fleeing, Ms Kelso said.
Officers were on scene in minutes, finding the scissors with blood on the blades on a train track and Djentuh with two friends in a station bathroom.
Evidence will show Djentuh deliberately and with intent to at least cause grievous bodily harm plunged the scissors into Mr Tagaloa, Ms Kelso told the jurors.
Defence barrister Matthew Hynes said the trial was about what happened when a person runs out of choices.
"It's about defending yourself from what is clearly an imminent threat, coming in your direction in the form of a big man, in the form of someone who has already proven that they can do serious damage to your two friends and he did that in a matter of seconds," he said.
"Having flattened those friends, he stomped on one of their heads on the cold, hard ground."
Mr Hynes said footage would show Djentuh backing away with two injured friends - one hobbling and the other with a bleeding eye - behind him.
The trial before Justice Glenn Martin is expected to continue for about seven days.
