Everton scouts were in Portugal this week to see Porto defeated by Champions League opponents Liverpool.
A Bola says Everton scouts were in attendance for Porto's Champions League quarter-final defeat to city rivals Liverpool on Wednesday.
Midfielder Jesus Corona impressed for the Portuguese side in their 4-1 defeat while Yacine Brahimi, who has been linked with the Blues in the past, also featured.
The 12-goal winger's contract expires at the end of this season.