Saturday's game in Buenos Aires between Argentina and Italy has become a grea deal more significant than ever seemed likely. Shortly before the World Cup began, Lajos Baroti, coach of Hungary, said as his team trained at Lon-Wembley Stadium that he believed that if both teams had qualified by then, they would be content to play a draw.

But with Italy's superity in goal difference - 5-2 to Argentina's 4-2 - all that may well be changed. A draw would leave Italy at the top of the group, and therefore condemn Argentina to play-away from its beloved Buenos Aires in the last, two-pool stage of the competition.

Ceasar Menotti, the Argentinian coach, admitted after his team's shaky 2-1 loss to France that he would much rather stay in Buenos Aires, near where the players are in camp, than go north to Rosario.

For the Italians, Buenos Aires would be just fine. It has a huge ItaloArgentine population, and each game for Italy would be virtually a home game. On the other hand, Enzo Bearzot, the Italian coach, is privately worried that excessive euphoria could turn into excessive displeasure if results weren't good.

There is every prospect that they will be. Italy, stimulated by the cold, bracing winds of Mar del Plata, has been surprisingly impressive.

The Italians came to Argentina with a bunch of tired, heavily criticized, players, with their own journalists lashing them after a dreary 0-0 draw with Yugoslavia in Rome. They have proceed to beat France after being a goal down, and now they have had little trouble with the weakened Hungarians.

The point is, as the shrewd Bearzot knows so well, that with Italian footballers, it is all in the mind. For years, they convinced themselves they couldn't run as hard and long as the Northern Europeans, the consequence being that they closed up meanly and timorously on defense.

Bearzot has been trying desperately to drag them out of such a posture, into the modern age, but with such huge sums of money involved, fear remains the keynote of the Italian championship.

Luckily for Bearzot, if has thrown up on the Darwinian principle the bonus of Paolo Rossi, a center-forward, 22 years old, valued at nearly 6 million, who has "come good" at exactly the right time, as every World Cup manager prays. Bearzot must be smiling his Chief Sitting Bull smile. He has had the laugh again on his bitter denigrators.

When he took office after the 1974 world cup, at first in harness with the veteran Fulvio Bernardini, he was covered with contempt. Journalists pointed out that he had never been manager of a major league club.

Instead, after a playing career with Internazionale of Milan, Torino of Turin, and a happy spell in Sicily with Catania, he went into the Italian Soccer Federation's coaching center, Al Coverciano, outside Florence.

Many a man would have been destroyed by such sustained and often ill-natured attacks. Bearzot, who comes from Friule in the northeast, was educated by Jesuits, studied Latin and Greek, and was once destined to be a doctor, is of hardier stuff. Endlessly smoking frequently smiling, easily wounded but never discouraged, speaking so quietly and allusively that is sometimes is quite hard to follow him, he took Italy to the finals of the World Cup at England's expense, and now his team is in the last eight.

He can, of course, at times turn a blind eye to his players' excesses. If you tell him that Romeo Benetti, scorer with a stupendous shot against Hungary, is a very hard man, he smiles and replies, "but he breeds canaries," which is true but scarcely relevant.

He will scarcely be very happy about the decisions by the Swiss referee which again went Argentina's way when that team beat France. The Argentinians got a penalty kick - which I am not prepared to challenge - but they should certainly have had one against them late in the game when Didier Six was brought down clearly in the box.

Six also forced a dazzling save from the Argentinian goal keeper when Michel Platini splendidly sent him through alone, earlier in the half. Alas, he shot past the post.

Restoring the two dominiaques from Saint Etienne, Rocheteau on the right wing, Bathenay, though still obviously not quite fit, to the midfield made all the difference to France, which went out with great honor. France's delicate but incisive forward play really showed up the weaknesses of the Argentinian defense, but when a team has two big strikers of the superb caliber of Leopoldo Luque and Mario Kempes, it can always pull rabbits out of the hat.

Luque's marvelously struck right-footed winning goal was a dazzling example of it. But I wonder how long Cesar Menotti would have gone on pulling off Daniel Valencia and putting on Norberto Alonso in left midfield, had Alonso not been hurt and taken off, soon after he had actually come one.

Presumably Alonso will now have to be sidelined, giving Valencia, who once almost scored with a beautifully executed left-footed volley, the chance of playing 90 minutes instead of less than an hour.

The avalanche of goals scored by the West Germans against the Mexicans proved two things. First, that with three forwards up instead of two, and Hansi Mueller joining to eagerly from behind them, the Germans still can be a strong challenger. Second, Mexico had no real right to be there. But as long as the qualifying tournament is divided into regional groups, so many fiascos will continue. It is at least some consolation for the United States, which really won't have to improve out of recognition of qualify itself in the not very remote future.

Poland presumably will chew up Mexico in Rosario on Saturday to stay in the tournament, but its meager 1-0 win over Tunisia did little to remove the aura of disappointment and flacidity which hung about it when it drew that dreadful opening game with West Germany. The Ebullient Poland of 1970 is now little more than a happy memory.

Happy, too will be the memory of France, with the glorious skills of Michel Platini, the infinite power and resilience of its sweeper, Marius Trescor. The World Cup will miss them.