The Dragons finished last season as Benfica went on to win the title.
FC Porto will open the new season with the Portuguese Super Cup against Benfica, the annual curtain-raiser for Portuguese football before the start of the new season.
Rayo Vallecano, on the other hand, will compete in Spain’s La Liga and travel to Almeria for the league opener on August 11.
Where to watch the game
The match will be streamed live on Portuguese broadcast media
Portugal: Sport TV1 , Sports TV Multiscreen, Porto Canal