Brazil have already booked their place in next year's World Cup, and Argentina are not far behind. They've hit the magic number of 28 points after 12 games, which has always been good enough in past campaigns, and there are several rounds still to go, including Tuesday's clash of the South American titans.
This edition of Argentina vs. Brazil, then, is of little relevance to World Cup qualification, but it could be of great relevance to the World Cup itself. Freed of the pressures of making it to Qatar, the two teams can now focus fully on preparing a team for the tournament. And there are few stiffer tests than the one that each will present to the other on Tuesday.
The last defeat suffered by both teams was inflicted by the other. Argentina have not lost since falling to Brazil in the semifinals of the 2019 Copa America, while Brazil's only competitive reverse since the last World Cup came against Argentina in the final of this year's Copa. Both are unbeaten in qualification. But now the bar rises. Flaws and mistakes which went unpunished against lesser teams may now be exposed in the San Juan showdown.
Argentina have taken this game away from Buenos Aires, the traditional base for the national team, and up to the northern provinces, which may not please the players. The pitch in their usual home, River Plate's Monumental stadium, is highly regarded and seen as suiting the home team's passing style. Instead, a small town in one of Argentina's wine growing regions has the privilege of staging such a showpiece occasion; here are some of the points of interest heading into Tuesday night.
DEFENCE WINS TITLES
A glance at the qualification table reveals how few goals these two teams are conceding. In 12 games Argentina have let in only six goals, and Brazil just four.
This is an area of the Argentina side that's undergone a dramatic improvement since tournaments past. The emergence over the past few months of Aston Villa keeper Emiliano Martinez has been of huge significance. With both talent and strength of personality, his presence has helped spread a confidence through the defensive line that Argentina haven't enjoyed for years, while Cristian Romero's presence in front of him has also been important. He may be the country's best centreback in some time.
But there is a difference. Brazil rarely even look as if they are in the slightest danger of conceding; Argentina, meanwhile, sometimes seem to be defending at the limit -- as they were, for example, for much of Friday's game against Uruguay. Brazil will unleash more attacking talent than Argentina are used to, which means this meeting will certainly put Argentina's defensive credentials under the spotlight.
MIDFIELD CAN WIN MATCHES, TOO
One of the great strengths of the current Argentina side is its midfield passing. Leandro Paredes plays the first ball out with quality, Rodrigo De Paul has a fine range of passing and Giovani Lo Celso has a sweet thing going with Lionel Messi. Moving the ball with such fluidity has helped Messi receive possession in pockets of space from which he can pull a rabbit out of the hat.
So how will Brazil line up against them?
Coach Tite has been moving towards a 4-4-2 formation, with Neymar floating up front behind a striker -- which could be Matheus Cunha on Tuesday -- and width provided by a winger (Raphinha) on one flank and an playmaker (Lucas Paqueta) on the other. Paqueta is splendidly versatile and may be better employed infield, especially in this game. The danger of the 4-4-2 against Argentina is that the two in central midfield -- Fabinho (stepping in for the suspended Casemiro) and Fred -- can be outnumbered. If Brazil go with this formation then full backs Danilo and Alex Sandro will be expected to help out.
The best place to look to stop Argentina is in midfield -- a lesson Uruguay had to learn when they went down to a 3-0 defeat last month, and which they took on board last Friday when they were unlucky to lose by the only goal.
Brazil look set to make an interesting change at centre-back. In the final of the Copa America, the immaculate Marquinhos was partnered by Thiago Silva, though this always looked like a mistake. Thiago Silva remains a fine defender, but he is at the veteran stage of his career and at the club level, he operates in reduced space, in the middle of the back three, with the pace of Antonio Rudiger alongside him a crucial part of the Chelsea defensive unit.
As part of a centre-back pairing, Thiago Silva is obliged to cover more space, and it was noticeable in the Copa America that Brazil did not press as well in midfield when he played. He preferred to drop deeper to give himself some breathing room, something that played a part in Argentina's winning goal, when Rodrigo De Paul had time to pick his pass for Angel Di Maria.
It seems that the very quick Eder Militao will replace Thiago Silva for this game. With Tite also having Gabriel Magalhaes available, Brazil have an embarrassment of defensive riches; with fast centre-backs, it should be easier to close down Argentina in midfield.
THE IMPORTANCE OF CONTROL
Part of the story of Argentina's Copa America triumph in July was the lack of emotional regulation from the Brazil attack when they were chasing the game. This has often been an area where Neymar can be questioned. In the words of former Brazil striker Paulo Nunes, Neymar "feeds off little disputes" with opponents and with referees. His style of play is always likely to lead to conflict with the ref; Neymar has his own criteria, where in his mind every contact he suffers is a foul, and he can lose control when decisions do not go his way.
He is, of course, a magnificent footballer, and his partnership with Lucas Paqueta has been the best thing about the Brazil attack in the last few months -- they even worked together to fashion a superb game-winning goal against Colombia last Thursday. But Paqueta can also be guilty of a petulant lack of maturity, and such a lack of calm cost Brazil in the final of the Copa America; it threatens to cost them under pressure in next year's World Cup.
This match will be good practice -- even if Neymar has been forced to miss the game, pulling out after feeling a muscular injury in Monday's training session. The test now is the extent to which Brazil can fire on all cylinders without him, as this game can serve as a rehearsal for a vital World Cup game should their most potent attacking weapon either be injured or suspended.
The teams met -- or started to meet -- in Sao Paulo back in September. That match, of course, was halted after five minutes, 10 seconds when Brazilian health officials wandered on to the field with the aim of expelling Argentina's Premier League players. But even in that short span of action, there were already hints that Brazil were having problems against the rival midfield, and that the Argentina defence would have trouble holding the opposing attack. This time, we have the full 90 minutes to put the teams under the microscope and judge the strength of their 2022 World Cup challenge.