UEFA has fined Porto 20,000 ($AU 26,000) euros after the club's supporters were found to have racially abused Manchester City striker Mario Balotelli.
The punishment was confirmed on Tuesday following a meeting of the governing body's control and disciplinary group last week.
The Premier League outfit initially lodged a complaint after the Italian striker was subjected to monkey chants during City's Europa League win at Estadio do Dragao in February.
Roberto Mancini's side eventually sealed progress against the Portuguese outfit with a 4-0 return-leg scoreline at Eastlands.
Porto have three days to appeal the decision, with the club initially claiming that their supporters had been chanting the name of Brazilian striker Hulk.
UEFA dismissed the claim, saying: "The UEFA control and disciplinary body has imposed a fine of 20,000 euros on FC Porto for racist conduct of their supporters at their first-leg round-of-32 UEFA Europa League match against Manchester City FC on February 16 in Porto."