The weekend's Peel Football League was marred by violence on Sunday afternoon when a brawl broke out at Bendigo Bank Stadium.
Waroona and South Mandurah were vying for premiership honours before a crowd of about 3000 when what was described by police as an "all-in brawl" erupted late into the last quarter.
A 19-year-old man and a 54-year-old man were injured during the melee with both conveyed to Peel Health Campus for medical attention.
It is understood their injuries are not considered to be serious.
Mandurah response teams, including detectives and traffic officers were deployed to the incident, with up to 20 police officers in attendance at the scene;
A 20-year-old man was taken into custody and is assisting police with inquiries.
Police said they believe alcohol was a factor in the violence and investigations are continuing.
South Mandurah won the match.