Police are appealing for witnesses following the incident in Malvern Way, which happened at around 3.30pm.
The victim, a 24-year-old man, was taken to hospital with wounds consistent of being stabbed with a sharp implement.
Police said it is thought the victim was there to meet the suspect before he was attacked.
Sussex Police added officers secured the scene around 3.35pm and were providing reassurance to the local community.
Police said they are keen to identify a black teenage man with a cornrows style hairstyle.
A search was conducted at an address in Hastings but no one was present.
Detective Inspector Sophie McGarel, said: “We appreciate this is a distressing incident for the local community, but I’d like to offer reassurance that we are treating it as an isolated incident involving two people known to each other, with no threat to the wider public.
“We would urge anyone who lives in the area who has a video doorbell footage or information which could help officers with our investigation to come forward.”
If anyone has information or video footage they should report it to police online or call 101 quoting serial number 896 of 25/11.