Porto will host Chelsea in the Champions League first-leg tie on Wednesday at Ramón Sánchez Pizjuán Stadium.
But Morais, who was on Jose Mourinho’s staff at Stamford Bridge during their time together at Chelsea, believes Porto can upset the Blues.
“I am a bit divided here, and I would like Chelsea to have positive results. Ask what I prefer, as a Portuguese, I prefer a Portuguese team to win,” Morais told O Jogo.
“What is comparable is FC Porto as an organisation and a demanding mental attitude. Any coach who passes by has an obligation to embody these values and be able to pass them on to the players. I believe that Mourinho did it and Sérgio is doing it.
“He may have received some influence in the way of training, but, in the rest, they are different personalities, moments and teams. There is no way to compare.”
Porto had eliminated Juventus from the Champions League last-16 in March, while Chelsea knocked Atletico Madrid out from the competition.