Police have named the 19-year-old who was attacked and knifed in Blackheath as Jordan Wright from Catford.
Medics treated the teenager for stab wounds at the junction with Hervey Road and Begbie Road, on Wednesday before he was rushed to hospital, where he later died.
Officers have launched a murder probe, and are appealing for a group of men thought to have been with the victim before the attack to come forward.
Detectives from the Met’s Homicide and Major Crime Command are investigating the incident, which happened near a sports field.
No arrests have been made, and police in Greenwich are conducting additional patrols in the area.
The officer leading the investigation, Detective Chief Inspector Diane Tudway, said: “I believe Jordan was part of a group of young men who had entered the park together before he was stabbed.
“Those other young men will know who they are, and I urge each of them to call police or Crimestoppers and simply describe what they saw.”
Anyone with information is asked to call the incident room on 020 8721 4005 or via 101.
To remain anonymous, contact Crimestoppers on 0800 555 111 or via the crimestoppers-uk.org website.