Michel Platini, regarded by many as the world's best soccer player, finally made his presence known at the 13th World Cup. And with him, France strengthened its claim to an elite position in international soccer.

With Platini -- who, during the early stages of this competition, looked as if his mind were elsewhere -- moving smartly and scoring the game's first goal, France dominated defending world champion Italy, 2-0, today at Olympic Stadium to advance to a quarterfinal meeting Saturday against Brazil.

In the day's second game, in Monterrey, Lothar Mattaeus put in a free kick from 30 yards with two minutes remaining to give West Germany a 1-0 victory over Morocco. The West Germans will play Mexico Saturday.

The Italians now must wait for the 1990 Cup, on home turf, to make another attempt to win their fourth world title. The French, meanwhile, may look at this victory as a watershed day on which they fulfilled much of the potential they demonstrated in winning the 1984 European Cup.

"This was important for France," the team's coach, Henri Michel, said. "Since 1920, we have not won over Italy. This is a great day, an important day for France, and I am enormously satisfied."

Platini, who had seemed sluggish in France's first three Cup matches, played with imagination and intensity. His midfield teammates -- Alain Giresse, Jean Tigana and Luis Fernandez -- were marvelously creative. And Maxime Bossis led a nearly flawless defense.

"I do not know if the criticism of Platini in earlier matches was justified," Michel said. "He played within the framework of the team and we just were not getting sparkling results. Today, he again played like the team leader he is, and it showed."

France never had beaten Italy in previous World Cups, losing, 3-1, in 1938 (in France) and 2-1 in 1978 (in Argentina).

Does this signal a changing of the guard in European soccer? "I don't think this victory can be thought of in that way," Italian Coach Enzo Bearzot said. "They've been good for years, a power since 1978. Perhaps now, they have reached their maximum potential and maturity . . . France was far superior in all aspects today, without exception."

Seldom in World Cup history has Italy been outplayed so decisively. In a 55-minute span beginning midway through the first half, the Italians managed only one shot on goal.

The tale of the game can be simply told: the French controlled the midfield and attacked with vision; the Italians looked tentative on offense, still in search of a striker to recapture Paolo Rossi's 1982 magic.

As was the case in his team's previous matches, Bearzot did not activate Rossi for the game.

France showed offensive versatility. In addition to its clever short-passing game, the French were aggressive from farther out. Fernandez nearly scored on two long-range rockets in the first half -- he was wide left on a 35-yarder and hit the crossbar from 45 yards out.

France took a 1-0 lead in the 14th minute by capitalizing on a midfield change of possession and catching Italy in transition. Fernandez pushed the ball quickly down the middle of the field and fed Dominique Rocheteau, who passed to Platini on the right side. From just beyond the penalty area, Platini beat his defender on the dribble, drew out goalkeeper Giovanni Galli and tucked a shot into the left corner of the net.

" Giuseppe Baresi was our man to mark Platini, then we tried Fernando de Napoli," Bearzot said. "It was difficult to both mark him and counter France's very strong midfield."

France made it 2-0 in the 13th minute of the second half on a controlled fast break. Tigana dribbled down the middle, avoided three defenders and veered to his left as he approached the penalty area. He centered to Rocheteau, who immediately pushed the ball to an unmarked Yannick Stopyra on the right side. Stopyra scored easily from 10 yards.

Rocheteau's two assists and Stopyra's goal came as wonderful news for the French: their strikers have been regarded as the team's weak link, unable to finish plays.

The Italians looked beaten even before the second goal. Once again, Italy's vaunted counterattack took the day off. Strikers Alessandro Altobelli and Giuseppe Galderisi seldom touched the ball near the goal.

Despite the French domination, this was one of the Cup's best matches to date, devoid of the over-rough play and open hostility that have marked many of the tournament's games. Both nations' players know each other well -- Platini, for instance, is a star with Juventus of the Italian league.

In the second game, the Moroccans -- the first African team to advance to the Cup's second round -- played a strong defensive game against the favored West Germans and it looked as if regulation play might end without a goal scored.

But suddenly Matthaues, who was robbed seconds earlier by goalkeeper Badou Ezaki, put his free kick past the Moroccan defensive wall and into the right corner of the net.