MILAN, JUNE 7 -- A fashion capital of the world and home of a great soccer club, this city will combine a day of extraordinary entertainment and serious sport Friday as the 14th World Cup finals begin with the fabulous 5-foot-5 Diego Maradona leading defending champion Argentina against long shot Cameroon.

"Milan has never experienced anything in sports that compares with this," said Silvano Tavceri, a press officer for Italia '90, the month-long tournament's organizing committee. For the opener, about 80,000 spectators and 1,700 journalists will pack Giuseppe Meazza Stadium, also called San Siro for its district. If only the game lives up to the hype.

Cameroon President Paul Biya promised that his "Lions of Africa" will surprise people in this prelude to play in 12 cities.

"This is not only an honor which the whole world is paying for our sports movement, and in particular our football," he said, "but also a stimulus which will give the Lions unbeatable strength."

To which Argentina's fans chuckle. Word from Buenos Aires is that the government is not even going to declare a national holiday, deciding not to close state offices on the strength of the Argentina-Cameroon match. Cameroon? Forget it. It'll be business as usual.

Certainly, Maradona, the prima donna, appeared unworried at a light workout in the city. The star of the 1986 World Cup showed up an hour late, then drifted about the field for 25 minutes and sauntered away when he felt like it.

He showed no ill effects from an ingrown toenail that had been bothering him, walking and jogging normally. An enterprising journalist who actually got a look at Maradona's toe up close said it looked like anybody else's big toe.

The United States, appearing in the Cup finals for the first time since 1950, will open its three-game first-round schedule Sunday in Florence against Czechoslovakia. Bob Gansler, the American coach, called the impending confrontations "the sporting challenge of our lives."

The odds say the Americans will not reach the second round. As for winning the Cup, the odds range from 200-1 to a London establishment's 2,000-1. Las Vegas odds, which reach even to Italy, placed the Americans at 20-1 to win a first-round game and 7-1 just to tie a first-round game. Czechoslovakia is favored Sunday by 1 1/2 goals.

"If you come into the U.S. camp, you'd find the odds 1 to 1 that we will win the World Cup," said Tony Meola, the two-time all-American goalkeeper from the University of Virginia and college player of the year last fall. The dark-haired, green-eyed budding idol in Italy, where his father was born and played some professionally, had come from the Americans' seaside training compound to Florence with the rest of the team to pick up credentials.

Maradona's expected antics, and spectacular pregame festivities that are scheduled to begin at 11:15 a.m. EDT, have brought the country's commercial center -- and home of European Cup champion AC Milan -- practically to a standstill.

Fashion models, 150 of them, will show off attire worn on the four continents represented by teams. Gymnasts will wave the flags of the 24 competing nations. Nothing less than a La Scala opera production will conclude the warmup.

Argentina's followers say their team this year is in the hands of the doctors. In the last Cup, Maradona leaped high and used what he later called "the hand of God" to score the first goal of Argentina's 2-1 quarterfinal victory over England. The goal was allowed to stand.

Now the doctors must decide if injured defender Oscar Ruggeri and scoring machine Jorge Burruchaga will be able to play against Cameroon. Word is never to rule out an Argentine player, and not just because the team's coach, Carlos Bilardo, is a doctor of medicine too. Too much is at stake and they'll play if at all possible. Journalists world wide scoff at Maradona, saying he was merely setting up an excuse with his toe in case he proves to be beyond his prime, a victim of easy living at 29.

Italy, Brazil, West Germany and the Netherlands, in particular, are ready to push Argentina and Maradona aside and become the '90 champion. The three Dutch stars -- Marco Van Basten, Ruud Gullit and Frank Rijkaard -- all play their club ball for AC Milan, one reason much of the discerning audience here Friday will expect a worthwhile show.

The only problem could be the field at San Siro. Turf was put down only in April after Italian players called the previous field a "potato patch." Otherwise, the stadium is a technological wonder -- in all, a steel-and-glass temple.

Refurbished as it is, it stands as a monument to Giuseppe Meazza, a great and colorful Italian player of decades past who was known for his bicycle kicks and free-wheeling off-field behavior. He died in 1979 at the age of 69.

The latest stadium work was spurred by soccer-crazy city officials and because of local tradition represented by clubs AC Milan and Internazionale. Maybe for more than Friday the city is legitimately the "football capital of Europe."

But starting Saturday, play will begin across the country. Italy is prepared to handle hooligans harshly, most recently sending home an Englishman who shouting derogatory remarks about the Dutch while wandering across the railroad tracks of the Termini in Rome.

Italy has rushed to prepare for the tournament, something it isn't accustomed to doing, and in the process there literally have been casualties. Twenty-five men have died and almost 700 have been injured at Cup construction sites.

The work goes on even on the eve of the tournament. Leaks in new roofing at Rome's Olympic Stadium were discovered when rain hit hard there. But there's still time because it will not be until July 8 that the championship match will be held in Rome, where all roads still lead.