It happened around 10:15 p.m., when the teen was stabbed on Rosslyn Avenue North, south of Barton Street East. Fans from the Canada and Brazil soccer game were still spilling into the streets in that area at the time.
According to police, the teen was involved in a fight with three other men, when one of them pulled out a knife and stabbed him.
The three men then ran off before police arrived. Hamilton police officers taped off the street while police dogs searched for suspects, but came up empty.
"The suspects were able to escape the area and avoid police," a police news release reads.
The teen was taken to hospital with serious injuries. He remains in serious but stable condition.