The Hammers have slapped a life ban on thirteen supporters over crowd violence.
Some West Ham fans fought among themselves and also clashed with stewards and visiting supporters at the London Stadium during the 4-2 loss.
The Premier League club released a club statement following the game which read: "West Ham United unreservedly condemn the behaviour of the individuals involved in incidents during the fixture against Watford.
"While these isolated incidents were quickly brought under control, this behaviour has no place in football and West Ham United will work tirelessly to eradicate such incidents.
"We are currently undertaking an immediate full review with all stakeholders. This includes police, stadium landlord and operator LS185, who are responsible for appointing and managing stewards and security, to ensure we eradicate such incidents moving forward."