Portugal versus Spain represents the first truly eye-catching match of the 2018 World Cup. The clash pits the European Champions of 2016 against the European Champions of 2012 and 2008, and sees Real Madrid star Cristiano Ronaldo face off against some of his club colleagues and Barcelona rivals.
Kick-off: 7pm BST
Portugal: (3-0 Algeria, 0-0 Belgium, 2-2 Tunisia)
Spain: (1-0 Tunisia, 1-1 Switzerland, 6-1 Argentina)
Portugal (4-4-2): Patricio; Cedric, Pepe, Fonte, Guerreiro; B Silva, Moutinho, Carvalho, B Fernandes; Guedes, Ronaldo
Spain (4-3-3): De Gea; Odriozola, Pique, Ramos, Alba; Koke, Busquets, Iniesta; D Silva, Rodrigo, Isco
WHAT WILL HAPPEN?
Spain's preparation for this match couldn't have been much worse. Julen Lopetegui, the coach that led them to the finals in fine form, was sacked just days before the tournament got underway after agreeing a contract to join Real Madrid after the tournament. As a consequence, Fernando Hierro will now take charge of the team.
Changing manager with a World Cup about to get underway isn't seen as good practise, though it's difficult to imagine this Spanish national team forgetting everything they have worked on in the past two years. Even without Lopetegui's presence, their intense pressing game, which we analysed in our tactical preview of the team, should still be in place; so too should their high tempo possession play.
Assuming there is no organisational or motivational drop-off as a result of the last few days of uncertainty, Spain should play the same type and quality of football that they played in the lead-up to the finals. Against a Portugal side that tends to prioritise defensive solidity, that should see them dominate possession.
The major issue for Hierro's players will be turning control of the ball into scoring chances. Fernando Santos' Portugal are, at their best, an extremely compact defensive unit; they do not give opportunities away easily. Their centre-backs, Pepe and Jose Fonte or Bruno Alves, are not blessed with pace, but this is mitigated by the fact they are rarely left isolated in 1v1 or 2v2 situations where their lack of mobility could tell.
Faced with a Spanish outfit packed with technically outstanding individuals, Portugal will probably look to congest the centre of the pitch and take away any space for penetrative passes to open up their midfield line. But they won't merely soak up – they will also threaten in attacking transitions.
Goncalo Guedes could start up front alongside Ronaldo, and it's hard to think of a more dangerous front two on the counter-attack. The latter's ingenuity coupled with the former's sheer pace could well pose Spain's central defensive pairing of Gerard Pique and Sergio Ramos problems.
Spain have scored in every game they have played since their Euro 2016 second round exit, so it's hard to see them not doing so here. However, Portugal have the defensive organisation to soak up their opposition's possession, as well as the speed and skill to create opportunities on the break.
For Portugal, the key man could be Bernardo Silva. Spain left-back Jordi Alba is renowned for his proclivity for forward runs, and he is tasked with attacking his flank in the offensive phase. This may open up space for Silva to exploit on the counter-attack.
In Portugal's friendly draw with Belgium, the Manchester City man pulled out to the right-hand side on the break to find space and isolate himself up against a defender. From there he would look to drive in onto his favoured left foot and create a chance or have a shot. His incisive dribbling and precise passing could prove pivotal in his side's brief moments of possession here.
As for Spain, it's difficult to look past the iconic Andres Iniesta as the tactical game-changer for their World Cup opener. Playing the more advanced role within a midfield three, he will look to get between the lines and create a 3v2 overload against the Portuguese central midfielders.
The 34-year-old's intelligent movement, control in tight spaces and ability to beat a man could be influential in unlocking a stout defence.
Expect Spain to control possession, though they may struggle to create chances from open play. What could prove more productive is their aggressive counter-pressing high up the pitch following moves that have broken down. This tactical facet could be particularly helpful against an unwieldy centre-back pairing of Pepe and Fonte/Alves.
Portugal will, for the most part, look to defend and counter. They could have some success with this strategy, but not enough to pose a concerted threat against a high tempo possession and counter-pressing side. Spain should get the goals they need to seal victory, but it might not look as pretty as some expect.