Officers were called to the Churchill Estate, SW1 at 8pm on Thursday, 11 June following reports of a fight.
On arrival, officers were confronted by around ten men fighting.
An 18-year-old man and a 19-year-old man were arrested at the scene on suspicion of causing grievous bodily harm. They were taken to a central London police station and later released on police bail. Both are due to return in early July.
A man, aged in his 40s, received injuries to his face, neck and back.
Officers at the scene reported that several witnesses were filming the incident on their phones.
Detective Constable Laura Guise, of the Central West Basic Command Unit (BCU), said: “We are aware that a number of people witnessed this violent attack. I would ask anyone who may have seen this incident and has footage on their phone to contact me.”
Anyone who may have been present that evening is urged to contact police on 101 quoting reference CAD 6671/11Jun20.