Officers responded to a report of two men assaulting a man during an altercation in Sea Road at about 4pm on Thursday (April 15).
The victim – a 20-year-old man – suffered a stab wound to the abdomen and was airlifted to hospital.
His injury was initially thought to be life-threatening but thankfully he is now in a stable condition, confirmed a Sussex Police spokesman.
Enquiries to locate the two suspects are ongoing, they added.
Detective Inspector Kim May said: “Our investigation is progressing quickly as our teams are working around the clock to establish the circumstances of this incident and identify the two suspects.
“We continue to appeal to anyone who saw what happened or any suspicious behaviour in the area such as two suspects running away.
“Please be assured that this event is being treated as isolated and not linked to any other incident.”
Insp May said there was nothing at this stage to suggest that there is any threat to the wider community.
“Local residents can expect to see an increased high-visibility police presence and proactive patrols in the coming days,” she added.
“We would like to thank them for their understanding while our investigation is ongoing.”
District Commander, Chief Inspector Jon Carter reassured residents: “We understand that this incident may cause concern and we would like to assure the public that this matter is being investigated as a priority.
“Violence will absolutely not be tolerated and we are committed to taking robust action against those who cause harm and keeping the local community safe.”
Anyone with any information, or who witnessed anything suspicious in the area, can report it online or call 101, quoting Operation Treble.
People can also contact the independent charity Crimestoppers anonymously on 0800 555 111 or report it online at www.crimestoppers-uk.org.
Sir Peter Bottomley MP for Worthing West, who looks after East Preston, said he has visited communities affected by serious crime across Worthing and Arun.
He told his followers on Facebook: “While we understand recent reports of serious crime across Worthing and Arun are unlinked, this does not reduce our strong concerns for the families involved and the impact on our feeling of safety in our communities.
“I have visited the communities affected across Worthing, East Preston and Rustington over the past week and spoken to the residents affected as well as the police force investigating the crimes.
“No one should feel unsafe walking home at night, or taking their children to a playground, or visiting their local park.”
He said the ‘violence involved in these attacks cannot be tolerated and we all must ensure every effort is made neighbour by neighbour, community by community to support our police in their efforts to investigate these incidences so that the criminals involved know we have zero tolerance for it’.
And speaking about this latest incident in East Preston, he said: “We are all shocked at the reports of a violent incident in East Preston. Whether it was a disagreement that turned violent or a premeditated assault, this is very rare for our part of the south coast.
“If anyone has information, they know that they should give it to the police or to crime stoppers by telephoning 0800 555 111.”