Well, they could hardly say they hadn't been warned. The Dragons came to town and they met their slayer.
In April, Islam Slimani scored two goals in a 3-1 victory for his former side Sporting Lisbon against Porto.
Even this season, only three days before joining Leicester, Slimani struck the equalising goal in a 2-1 victory for Sporting against Porto.
It was six goals in six games while in Portugal and so it was again here, as Slimani left Porto's defenders reaching for the smelling salts once more.