The bloody attack took place at around 5am on Praia da Rocha’s main strip, Avenida Tomas Cabreira.
A large smear of blood on the cobblestone pavement was still visible later that day.
The victim was taken to Portimão city Hospital, where he was treated and stabilised before being rushed to the Santa Maria Hospital in the Portuguese capital due to the severity of his injuries, where he underwent surgery.
The Irishman was reportedly attacked by two men in Praia da Rocha; police are investigating the incident and are reportedly treating it as an attempted murder.
Some Irish press reports claim the man was stabbed “once in the shoulder blade, near to the armpit, and the blade narrowly missed the heart”, and that he “lost a lot of blood.”
Suggestions are the attack could be linked to an earlier altercation that occurred in a nightclub and spilled out onto the street, but could also be the result of a violent mugging.
PJ police reportedly now want to speak to the Irishman about the ordeal.
Praia da Rocha is the main tourist resort of the city of Portimão and is one of the most popular locations for nightlife-loving locals and tourists in the Algarve.