A 20-year-old man was taken to hospital with multiple stab wounds following an incident in Egremont.
Police were called to St Elmo Road shortly before midday to reports of a man lying on the floor with wounds to his leg, back neck and head.
He was treated by ambulance staff and taken to hospital where his condition is described as serious but non-life threatening.
Shortly after the victim was found, police chased and arrested a 22-year-old man from Birkenhead, on suspicion of a Section 18 assault.
The offender was also taken to hospital for treatment for slash wounds to his hands.
Armed officers were deployed to the area.
An appeal for witnesses has been launched.
Chief Inspector Mark Everard said: "Our officers acted quickly to detain the offender and it is because of their fast response we have been able to take the offender off the streets and into custody.
“I would appeal to anyone with any information about this shocking incident, in the middle of the day, to come forward to assist us in the early stages of this investigation.
"This is currently a live investigation and officers are at the scene on St Elmo Road and also at two further locations on King Street and Charlotte Road where we detained the offender just before midday.
"We are carrying out house-to-house enquiries, looking at CCTV and conducting forensic analysis.
"I would urge anyone with information to come forward quoting log 258 of 29 April.
"We cannot have this sort of reckless and brutal behaviour and we will do everything we can to bring the offender to justice."
If you have any information, DM @MerPolCC or contact @CrimestoppersUK or contact the independent charity Crimestoppers anonymously, on 0800 555 111 or online at https://crimestoppers-uk.org/give-information/give-information.