The A Selecao began their World Cup campaign with an exciting 3-2 victory over Ghana and followed it up with a 2-0 win against Uruguay and despite a 2-1 defeat to South Korea on a stoppage-time goal, still won Group H.
For Switzerland, they began the tournament 1-0 winners over Cameroon before falling to the top-ranked team in the world Brazil by the same score, setting up a winner-take-all showdown against Serbia with Remo Freuler's 49th-minute goal securing victory and passage to the knockout stages.
Portugal is looking to progress beyond this round for the first time since 2006 when they finished fourth while a win for Switzerland would equal their best-ever result, having made the quarterfinals in 1934, 1938 and 1954.
The A Selecao began the World Cup with question marks in attack, but the forward line has performed well. Joao Felix and Rafael Leao have both scored, making it an intense battle for a starting spot on the left.
Left-back Nuno Mendes is out injured and will play no further part in the tournament.
Portugal: Costa; Guerreiro, Pepe, Dias, Cancelo; Neves, Carvalho, Silva; Fernandes; Ronaldo, Félix
Switzerland: Sommer; Rodríguez, Elvedi, Akanji, Widmer; Xhaka, Freuler; Vargas, Sow, Shaqiri; Embolo
Cristiano Ronaldo (Portugal)
One thing is for certain: he's been the center of attention in Qatar, from his contract with Manchester United being terminated prior to the opener against Ghana to claiming a goal against Uruguay that he never touched, the 37-year-old is again always in the headlines.
Ronaldo scored against Ghana and, as always, will be pivotal for the A Selecao to continue their quest to win their first World Cup title.
Xherdan Shaqiri (Switzerland)
He's been terrific in the tournament and has the versatility to play as an attacking midfielder or winger. He is the conduit between midfield and attack, often playing in an advanced role just behind the forward line.
Shaqiri featured in six of the World Cup qualifying matches, scoring one himself and setting up five more, underlining his importance to Switzerland’s offensive capabilities.
Where is the match being played?
The match will be played at the Lusail Iconic Stadium with this being the first of four knockout matches contested at the venue.
Portugal played their 2-0 victory over Uruguay in the group stage at the 88,966-seat stadium.
What time is the match?
How can I watch the match?
In Portugal, Sport TV will televise the match while SRG SSR is carrying all of the action in Switzerland.
FOX will have the English-language telecast in the United States while Telemundo has the Spanish-language broadcast.