Portugal need a point against Group A rivals Serbia for automatic World Cup qualification after their 0-0 draw with Ireland.
Portugal avoided defeat against the Irish two months ago thanks to last-gasp goals from Cristiano Ronaldo and seemed content on taking a point against them on Thursday. Fernando Santos' team know a superior goal difference to Serbia gives them the upper hand when the teams clash on Sunday.
However, they will be without Pepe as the veteran defender was sent off late on for a second bookable offence. At least, there is the possibility of Manchester City star Bernardo Silva returning to the Portuguese team as he took part training late on Friday.
Silva had missed Thursday's qualifier due to muscle fatigue, but is expected to be fit for the match at home.
"We think he will be okay for Serbia [on Sunday]," Santos had said earlier.
"He arrived tired, complaining, he has many games on him, and couldn't go to training. But he's recovering well and we hope and we believe he'll be able to play here with Serbia."
If Portugal somehow slip up against Serbia, they will finish second and will then have to navigate through the play-offs for Europe’s three remaining places at the tournament in Qatar.