For this country, the hero of the Pan American Games has been swimmer Alberto Mestre, with a silver and four bronze medals in the sport that had the strongest fields here.

In honor of Mestre, born in New York of Cuban exile parents, fans hung a banner at poolside that read, "Viva 'Tiburon' Mestre, Venezuela Contigo," meaning, "Go 'Shark' Mestre, Venezuela Is With You."

When Mestre won the silver in the 200-meter freestyle behind Bruce Hayes, the crowd capped the victory ceremony by singing the Venezuelan anthem for Mestre.

The other night, Mestre, a University of Florida student, took U.S. swimmer Kathy Treible, also of Florida, out to dinner. Leaving the restaurant, Mestre discovered that one of his adoring countrymen had stolen his new car.

This is an election year in Venezuela and politicians are not reluctant to capitalize on what success the host country's athletes have enjoyed.

Rafael Caldera, candidate of the ruling Copei Party, noted the other day that Venezuela was fourth in total medals with more than 50, compared with only 20 in 1979, when the Accion Democratica Party was in power.

Caldera added that, although Venezuela had been eliminated from contention for a baseball medal, it had Venezuelan Tony Armas' 28 home runs for the Boston Red Sox as consolation.

On Tuesday, the governor and mayor of Caracas will present the Order Diego de Lozada, named for the city's founder, to all Venezuelan medal winners. Gold medalists will receive the order in first class, silver in second, bronze in third.

Refreshments at Pan Am Games sites are considerably cheaper than those sold at U.S. stadiums. Beer, for example, costs only about 40 cents from both vendors and refreshment stands.

Hot dogs adorned with onion chips, sauerkraut, mustard, ketchup and horseradish also cost 40 cents. Hamburgers are 70 cents.

Many stands sell local specialties like empanadas--pies containing meat or cheese--or toasted arepas--bread dipped in various relishes. Vendors outside the sites cook chunks of meat on braziers, shishkabob style.

All the sites are surrounded by youngsters with refrigerated carts, selling snow cones.

Shirts bearing logos of the games' mascot, Santiago the Lion, playing various sports are very popular at $4.

At the U.S.-Guatemala soccer game, played in the morning, only one stand was open at Brigido Iriarte Stadium. It offered native Indian handicrafts, many of excellent quality, but business was nonexistent for the woman who sat peacefully among her wares.

Although crowds root hard against the U.S., there has been only one distressing incident involving U.S. athletes. The innocent victim was Lisa Wittwer, a 14-year-old gymnast from Minnesota.

Preceding Wittwer on the uneven bars was a Venezuelan of mediocre talent. The spectators, however, cheered her routine enthusiastically and went wild when one of the judges' scores indicated a 10.

Unfortunately, the scoring system had become inoperative. When the official score was announced--far, far below a 10--the crowd became unruly and threw soda bottles and paper.

The fans booed throught the performance by Wittwer, despite a plea by the Venezuelan involved that they stop. Somehow, Wittwer earned a silver medal.