Porto are preparing to make a complaint to UEFA after Manchester City taunted striker Hulk during Wednesday's Europa League tie between the two sides.
The Portuguese club are unhappy with City chanting "you're not incredible" at Brazilian striker Hulk during City's 4-0 win at the Etihad Stadium.
Porto claim the chants are unsporting towards Hulk and have called on UEFA to take action against City.
Porto spokesman Rui Cerqueira said the matter would be reported on the grounds that City's supporters had acted in an improper way.
Hulk had also been targeted with chants of "cheat" because of the forward's perceived tendency to look for free-kicks and Porto will claim he was the victim of unsporting behaviour that warrants an official investigation.
The move by Porto comes on the back of the decision by UEFA to launch disciplinary proceedings into the complaints from City that monkey noises appeared to be directed towards Mario Balotelli and Yaya Toure during last week's first leg meeting between the two sides in Portugal.
Porto claimed the chanting last week was a misunderstanding and suggested that fans singing both "Hulk, Hulk, Hulk" and "Kun, Kun, Kun" for Sergio Aguero could be confused for racist chants.