#1 Portugal vs Spain (15 June)
Day 1 of the World Cup always sees the hosts play the first fixture but Day 2 is arguably the biggest day of the group stage. Apart from Egypt vs Uruguay, we will also see two Iberian sides battle it out in what is the biggest game of the group stage.
Portugal vs Spain is more than just a match. It is a clash of identities - a 'local rivalry' that will now be watched by billions around the globe.
For the two sides, this World Cup means a lot. Spain are trying to recapture their lost glory under new coach Julen Lopetegui while Portugal are looking to use their Euro 2016 triumph to make a case to win the big one.
The fact that they face each other as soon as the tournament kicks off will make this all the more important as they might not get a second chance to top the group. Both teams are expected to beat Iran and Morocco so this fixture will decide who tops the group to avoid a potential Round of 16 clash with Uruguay.
Will Cristiano Ronaldo be able to get the better of the combined forces of his La Liga counterparts Sergio Ramos and Gerard Pique?