A man was taken to hospital with serious injuries after being stabbed in the chest, arms and head in Bognor Regis on Sunday afternoon (March 10), police confirmed.
The alarm was raised at 5.36pm, police said.
According to police, a suspect ran off from Marine Park Gardens, leaving the victim, believed to be in his mid-20s, bleeding 'quite heavily'. He was taken to the Royal Sussex County Hospital in Brighton.
Officers attended and detained a man nearby about ten minutes later, a police spokesman added.
Police said: "Anyone who witnessed the incident is asked to report online or call 101 quoting serial 1237 of 10/03. If you see anyone with a knife in the street, please dial 999 immediately."
Police said a 23-year-old man from Barnet, London, was arrested on suspicion of attempted murder. He remained in custody on Sunday evening.
A police spokesman said there are no further details at present.