Uruguay have the World Cup edge in winning the tournament twice, albeit a few generations ago, and are more than familiar with Portugal, having knocked them out of the contest in 2018 in the round of 16.
Although Cristiano Ronaldo (37) stole the show on Thursday, setting a record by scoring in his fifth World Cup in Portugal's 3-2 win over Ghana, his team lacked inspiration and have much to do to shake off a dismal run of World Cup form since reaching the semi-finals in 2006.
Uruguay, while failing to score any goals or even record any shots on target in their opener against a gritty South Korea on Thursday, were composed, organised and like a team capable of another deep World Cup run, with veterans and neophytes combining seamlessly and moving the ball with confidence.
All five goals of Portugal's opening game came in a frenetic final 25 minutes likened by coach Fernando Santos to a storm. He said he is untroubled going into the Uruguay match because he knows what needs fixing.
"It's nothing I'm worried about because I know that my players can do better than that, but that's football," he said. "I am totally confident that they can perform much better than this."
Portugal, with a habit of going down to the wire in the World Cup group stages, may want to avoid that this time with a final match against South Korea, the team that ended Germany's title defence in 2018.
Equally, Uruguay will want to avoid defeat against Portugal so their fate can remain in the own hands in their final match against Ghana.
Uruguay have looked good since Diego Alonso took over late last year and turned things around in qualifying. He has every player available in his squad, except Barcelona's Ronald Araujo (23), recovering from thigh surgery.
Alonso's defence looked sturdy against South Korea and he is blessed with plenty of attacking options through Luis Suarez (35) and Edinson Cavani (35) - despite their age - and Liverpool's Darwin Nunez (23) and Manchester United's Facundo Pellistri (20), who looked dangerous on their World Cup debuts.
Alonso expects a tough game on Monday and for the group to be decided in the final match.
"Obviously the second game is key as is the third," he said. "Whether we qualify or not depends on us."
Follow all the action from Uruguay versus Portugal on Flashscore.
