That, of course, means a battle with fellow City star, Manuel Akanji in the 19:00 encounter at Lusail Iconic Stadium.
If Portugal are to progress, Dias, as always, will be a key player.
He's played at the heart of the backline in two of the three Group H games as Portugal finished top of the pile.
Now for the Swiss!
With City, of course, Dias has been a commanding presence at the back.
After joining in September 2020, he enjoyed a brilliant debut campaign, winning Premier League Player of the Season, Football Writer’s Player of the Year and Etihad Player of the Season.
With him in the backline, City enjoyed a watertight defence, conceding the fewest Premier League goals as well as lifting the Carabao Cup for a fourth successive season.
Dias was again outstanding in 2021/22, despite an interrupted second half of the campaign due to injury – and was often wearing the skipper's armband in Fernandinho's absence as City defended our Premier League crown.
He's made a solid start to this season as he now focuses on his country before attention turns to club once the campaign begins again later this month.
Watch the video above to see some of Ruben’s best highlights in a City shirt...