A youth admitted stabbing an entrepreneur and budding male model in the heart but claimed it was self-defence, a court heard.
The 17-year-old, who cannot be named for legal reasons, and 21-year-old Aaron Kahrod have denied murdering James Brindley, 26, in an altercation in Aldridge, near Walsall, West Midlands, on June 23 last year.
Mr Brindley had been fatally wounded in a 35-second gap between two phone calls from his Manchester-based girlfriend Lauren, at 11.42pm.
Opening the case, Prosecutor Jonas Hankin QC said witnesses had seen shoving and one of the defendants push two arms towards the Aldridge man's chest - forcing him to stagger backwards.
Despite the youth's admission that he stabbed Mr Brindley, he, and Kahrod, of Walsall Road, Aldridge, pleaded not guilty to murder, with the latter denying "any unlawful part in the incident".
Birmingham Crown Court heard Mr Brindley lived with his parents which was "400 metres or so" from where he was to "collapse and die from the stab wound".
In the moments just after the incident, Lauren sent quickfire messages to Mr Brindley saying: "James? Please tell me you're OK. You need me to phone your parents? I'm scared to phone back, have you phoned an ambulance?"
This came after Mr Brindley sent Lauren Whatsapp messages, which read: "I've just been stabbed. Two secs, I'm calling an ambulance."
The prosecution said the 17-year-old had attempted to dispose of any evidence after the stabbing.
Mr Hankin told the jury: "(The 17-year-old) admits stabbing Mr Brindley but says it was in self-defence.
"Following the stabbing, the 17-year-old's first thought was to immediately dispose of evidence. It occurred to the 17-year-old to dispose of his clothing."
The jury then heard that a surgical face mask was found in the youth's coat, which he left on top of a bin.
Mr Hankin said the post-mortem confirmed a blade had "passed through the sternum and caused a fatal injury to the heart".
Reading through witness accounts of the incident, Mr Hankin continued: "The stockier of the two defendants shouted 'come on then', aggressively towards the man on the pavement.
"He shouted it aggressively as if he was calling him to fight."
Passers-by had performed first-aid "admirably" by fetching napkins from a nearby restaurant to place on the wound, but Mr Brindley was pronounced dead at 1.05am the following morning, Mr Hankin said.
Medical experts had performed open-heart surgery on Mr Brindley on the pavement shortly before his death.