Edinson Cavani and Luis Suarez line up in Uruguayan colours while world player of the year Cristiano Ronaldo will lead the line for Portugal.
The 33-year-old Real Madrid star is his country’s record goal scorer with 85 strikes in 153 games and has four goals in the 2018 tournament.
But Portugal coach Fernando Santos warned on the eve of the clash that Ronaldo cannot beat Uruguay all by himself.
"We have to play as a team,” Santos said. “If Ronaldo plays alone we will lose."
Santos, who steered Portugal to their first piece of international silverware at the 2016 European championships, added: "We have to be strong as a team, as strong as Uruguay. It is difficult to play on your own. Even if Ronaldo scores three goals, he has a team working for him."
Santos highlighted the depth of quality in the Uruguay side. "Their central defenders play for Atletico Madrid, who won the Europa League. In midfield they have one who plays for Juventus and one for Inter.
"Their strikers play for Paris Saint-Germain and Barcelona. Three of those sides won the league in their countries.
"It is true, though, that when both teams cancel each other out, that is where the individuals come to the fore.”
Suarez was attacked for his lack of sharpness in Uruguay's opening game against Egypt. But the Barca frontman insists he is in better shape and ready for the challenge.
"I always demand the maximum from myself,” he said. “I am always criticising myself. Having the support of my teammates helps and speaking to the coach is important too.
"You don't need any greater motivation than to see what is in play: the last 16 of the World Cup against the European champions. It doesn't get any better."
Uruguay claimed Group A with maximum points and they are the only side to have reached the last 16 without conceding a goal.
"Cristiano Ronaldo is the leader of their team,” said Uruguay coach Oscar Tabarez. “It won't just be one player marking him. There are things we need to do from a collective viewpoint to try to limit him.”