MEXICO CITY (AP) _ For host Mexico, the World Cup title match between Argentina and West Germany on Sunday marks the ends of a month-long fiesta and the return to grim economic realities.

Mexico's economy is in deep recession, crippled by high inflation, a declining job market and a crushing foreign debt.

The Mexican government is optimistic that promotional spots aired worldwide during TV broadcasts of the 52 World Cup games since May 31 will boost tourism.

More than 500 million people worldwide were expected to watch the live telecast of the championship match, while Aztec Stadium in Mexico City will be filled with 114,000 fans.

''We think that this is going to resound in an increased capacity,'' said Jose Salazar, a spokesman for the Tourism Department. ''It's not immediate. . . . Tourism is not something that happens from one day to the next.''

Salazar said that between 35,000 and 45,000 foreign tourists came specifically for the World Cup games. However, the magazine Proceso surveyed travel agents and hotels at the nine host cities and estimated the number at no more than 20,000.

The World Cup organizers had projected 50,000 foreign visitors - relatively small extra revenue for a tourism market that attracts four million foreigners each year.

Mexico stepped in to host the 1986 tournament after Colombia withdrew for economic reasons four years ago and became the first nation to organize two World Cups.

Mexico already was in the depths of its worst economic recession in half a century, but private enterprise, spearheaded by the affluent Televisa network, bore the brunt of the costs.

Most of the stadiums and other infrastructure already existed as leftovers from the 1970 World Cup.

The government and organizers have not released figures on the costs of staging the 24-nation tournament.

The government would say before the start only that it allotted $5 million for security, with an estimated 30,000 agents deployed at airports, hotels, stadiums and other strategic points.

Thousands of soldiers were also deployed at the 12 stadiums in nine cities, and the Mexican Navy patroled to discourage terrorist infiltrators.

When the decision was made to host the World Cup, the government forecast that the economic crisis would be over by the time of the tournament.

Instead, the price of oil - Mexico's main earner of foreign revenue - plunged this year, further burdening the economy. This summer will be a crucial period for international negotiations on Mexico's $97.6 billion foreign debt, the second largest in the developing world after Brazil's.

The peso currency slid precipitously in the opening week of the tournament, although it has since recovered about half the loss to trade at a rate of about 610 to the dollar. At the start of the year, it was quoted at 445 per dollar.

Mexico also remains seriously affected by the Sept. 19 earthquake that devastated the heart of Mexico City.

The World Cup, at least, gave hundreds of thousands of Mexico City residents an excuse to forget their troubles and celebrate. The weekly publication Punto, a frequent government critic, said the spectacle ''distracts attention from the crisis.''

Downtown streets were packed with revelers after Mexico's first victory June 3 in an outburst of soccer madness known as ''locura.'' But the joyous celebration turned ugly, with disturbances in downtown areas and vandalism at the Angel of Independence, one of the city's proudest monuments.

Police arrested 81 people and some 200 were injured. A high wooden barricade was thrown up around the monument so it could be repaired.

At least a million people turned out in Mexico City to celebrate Mexico's June 15 victory over Bulgaria that sent the host team into the quarterfinals.

Although the dream of winning the World Cup ended with a loss to West Germany on June 21, Mexico did finish No. 6 in the tournament, its best performance ever.

Ticket prices, ranging from $3 to $50 seat if bought individually, but often higher if purchased in package deals, were well out of reach for the average worker in Mexico, where the minimum daily wage is less than $4.

A top official of the international soccer federation, FIFA, criticized the Mexican organizers for selling tickets in series. Stadiums were half empty for some opening-round games.

Despite problems with ticket sales, the organizers reported that World Cup attendance had already topped 2.1 million before the semifinal matches, breaking the previous record set in Spain four years ago.