As Brazil coach Tite stressed the other day, there is no such thing as a friendly between his national team and that of Argentina. But some un-friendlies are more friendly than others. And Tuesday's meeting in Saudi Arabia falls into this category.
First, it comes in the silly season of South American national team football, the year following a World Cup in which no competitive games are played. These sides will not be in action with points at stake for another eight months, when the 2019 Copa America kicks off.
Moreover, there is a lack of symmetry between Tuesday's two teams. They find themselves in radically different states of preparation.
Brazil are hosts of that 2019 Copa, and so their urgency is far greater. Many will see the Copa as primarily a warm up for the 2022 World Cup qualifiers, which kick off soon after. But Brazil are under pressure to win the Copa -- and so while many South American sides are building for the long term, Brazil can only give it half an eye.
The rest of their vision is fixed on the short term, hence the fact that they have retained coach Tite, and that in the three matches since Russia 2018 they have used 14 of their World cup squad -- with centre-back Miranda set to make that 15 on Tuesday.
Argentina, meanwhile, are in no rush. The extremely inexperienced Lionel Scaloni is in caretaker command while they take their time to make a permanent appointment. Lionel Messi and many of his generation have not been called up -- for some, it could mark the end of their international career. Messi is expected, or hoped, to return at some point.
Scaloni, therefore, has been given free rein to build for the future -- the squad has been revamped. Only eight of those who went to Russia have re-appeared since, though the return of centre-back Nico Otamendi is expected to raise the figure to nine on Tuesday. Argentina, then, go into the game as outsiders, fielding an experimental side against much more consolidated opponents.
In Thursday's 4-0 win over Iraq, Scaloni employed at least three different systems, starting with his base formation of 4-3-3, switching to a 4-2-3-1, and ending up with three centre-backs and something akin to a 3-4-2-1.
He has talked of a desire to introduce a more direct playing style -- an idea best seen in the first half of his debut game against Guatemala last month, when his side ran up a 3-0 win. The passing of Leandro Paredes from central midfield was the key, switching the ball quickly and accurately to the wingers. The likelihood is that he will be joined on Tuesday by the combative Santiago Ascacibar, Javier Mascherano's long term replacement as midfield terrier.
There is a clear problem that Scaloni is likely to face -- moving the ball quickly could leave the side stretched out when the move breaks down, presenting Brazil with plenty of space in which to launch their lightning breaks. With Ascacibar alongside Paredes, and Maxi Meza and Eduardo Salvio running the flanks, Argentina will hope to be covered.
It is not clear whether there will be a place for Paulo Dybala, who was so much more effective in a central role against Iraq than when he featured wide. And despite a wonderful debut international goal from Lautaro Martinez last Thursday, it is likely that Mauro Icardi will start at centre-forward.
Brazil, in contrast, seem much more defined. The experiment with Fabinho at right-back was not a success against Saudi Arabia, and Danilo seems ready to return. Midfielder Arthur could be given his big chance, effectively in the role filled by Paulinho in the World Cup.
Manchester United's Fred has not made the position his own and so the Barcelona youngster, so impressive against Tottenham in the Champions League recently, should be given the chance to bring his passing game to the national team.
There does, however, seem to be one nagging doubt in the mind of coach Tite; where to use Philippe Coutinho.
His natural position is floating in from wide on the left -- a role filled by Neymar, who was outstanding against the Saudis. Coutinho broke into the side during the 2018 qualifiers playing wide on -- or from -- the other flank. During the World Cup, Tite took the bold step of using him as a genuine midfielder, on the left of the central trio. The big advantage is that this means he can get closer and combine with Neymar. The problem is that it leaves Brazil vulnerable in defence.
Against Saudi Arabia, Neymar spent much of the second half operating in a more central area, as he has been doing recently for Paris Saint-Germain. This could be the future, since it opens up the possibility for Coutinho to play in his best position. But this would entail a reconstruction of the side.
Tite likes to see his team as a 4-1-4-1, though it might just as well be described as a 4-3-3. However, Arthur sits deeper than Paulinho, whose best work came with his charges into the opposing penalty area. And so the addition of Arthur opens up the possibility of sacrificing a midfielder and moving to a 4-2-3-1, where Neymar can play behind the striker and Coutinho can go out to the left.
That would seem to be a worthwhile experiment, and Tuesday's relatively friendly non-friendly might be the right place to give it a try.