PAN AMERICAN GAMES : The Goal Here: <i> No Problemas</i> : Cuba: One soccer field may not be up to standards and weather is muggy, but everything else seems to be working. Opening ceremony is tonight.

Having arrived in Cuba and found most of the sports facilities adequate and their accommodations livable, both of which were guaranteed by El Comandante Fidel Castro but still had to be seen to be believed, 5,259 athletes from 39 countries are finally beginning to concentrate on their purpose for being here and in Santiago de Cuba: the competition.

The XI Pan American Games, involving athletes from North, Central and South America and the Caribbean, will begin tonight with an opening ceremony at the newly constructed Olympic Stadium, followed by 16 days of competition in 31 official sports.

The quadrennial event was created in 1951 to bring countries of the Americas closer through sports, but sports have not been the focus of recent Pan American Games.

In 1979, at San Juan, Puerto Rico, the U.S. men’s basketball coach, Bobby Knight, created an international incident when he became involved in an altercation with a Puerto Rican policeman.

In 1983, at Caracas, Venezuela, officials fired the first shots in the war against anabolic steroids with stringent testing that caught 17 drug users and sent several others fleeing in the night to the airport to escape detection.

In 1987, at Indianapolis, there were several confrontations between members of the Cuban delegation and anti-Castro demonstrators, and the Cubans threatened to withdraw from the closing ceremony when they discovered that a Cuban-American rock star, Gloria Estefan, would perform.

On the eve of the largest international event, sporting or otherwise, to come to Cuba since the revolution in 1959, the calm was interrupted only by concern over whether the soccer field at Santiago de Cuba’s Antonio Maceo Sports Center will meet international standards.

Officials of soccer’s governing body (FIFA) plan an inspection today and said they will announce their decision Saturday, 48 hours before competition is scheduled to begin there with a game between the United States and Suriname.

If FIFA rules that the field is inadequate, games involving the four teams that were assigned to play at Santiago de Cuba in the first round will be moved to an alternate stadium at Havana, which already was established as the site of the other four teams’ first-round games.

That will not inconvenience the U.S. Olympic Committee, which was not informed until this week that its soccer team was scheduled to play in a city 530 miles to the east of Havana, and has reservations in the athletes’ village for the 22 players and officials.

Another potential problem that not even El Comandante can correct is the climate. Temperatures this week have been in the high 80s and low 90s, with humidity to match.

Attempting to find a time when conditions will be least intolerable, organizers scheduled the start of the men’s marathon for 6:30 a.m. Saturday, followed 30 minutes later by the start of the women’s marathon. But times are expected to be slow, and medical teams will be on alert.

Sensitive to the “Ugly American” reputation that U.S. athletes have acquired within the region because of their loud complaints about conditions at past Pan American Games outside the country, USOC officials have acted since arriving in Cuba as if nothing could bother them, not even the absence of toilet seats in the athletes’ village. They released two pages of quotations Wednesday to the media from U.S. athletes, who were unanimous in their praise of the village.

The United States has the largest delegation with 685 athletes--76 more than Cuba--and, as usual, is expected to dominate the medal standings. Since 1951, the United States has won more Pan American Games medals than the next three countries--Cuba, Canada and Argentina--combined. Four years ago at Indianapolis, the United States won a record 369 medals, including 168 golds, to totals of 175 for Cuba and 162 for Canada.

The U.S. advantage no doubt would be more overwhelming if it entered all of its best athletes. With some notable exceptions, sports federations under the USOC umbrella send the same athletes to the Pan American Games that they do to the Olympic Games. But that is not the case this year in men’s basketball, boxing, gymnastics, swimming and track and field.

USA Basketball, which will use a team consisting primarily of NBA players in the 1992 Olympics, did not invite professionals to try out for the men’s team that will play in Cuba, and the other four high-profile sports have international competitions later this year that are considered more prestigious than the Pan American Games.

Some events to watch:

--Basketball. The favored U.S. men’s team consists of 12 collegians, including Christian Laettner, Grant Hill and Thomas Hill of Duke; Terry Dehere of Seton Hall, and Tracy Murray of UCLA. But with a team that included David Robinson and Danny Manning four years ago, it lost to Brazil in the final when Oscar Schmidt scored 46 points. The Brazilians are coy when asked whether Schmidt is on their team this year. “Wait and see,” they say.

The U.S. women, with experienced players such as Teresa Edwards, Lynette Woodard, Katrina McClain and Jennifer Azzi, are threatening to dominate opponents as the Soviet women did a decade ago. The United States has a 41-game winning streak in international play.

--Baseball. Cuba, which always seems to have three or four players with major league talent, has won gold medals in this sport at seven of 10 Pan American Games, including the past five.

But although the young U.S. team lost seven players in the recent amateur draft, it won two of three games against Cuba last month at Santiago de Cuba. It was the first time that the United States has won a series in Cuba. The Cubans are further concerned because their No. 1 pitcher, Lazaro Valle, has a blood clot in his right arm that might prevent him from playing again.

--Boxing. Olympic Festival champions were offered a choice between competing in the Pan American Games, against the powerful Cubans in their home ring, or in the World Championships next November at Sydney, Australia. All 12 left Los Angeles humming “Waltzing Matilda.”

The 12 Festival silver medalists are being thrown to the Cubans, but USA Boxing officials say it will be good experience for them.

--Tennis. Pam Shriver enjoyed the Olympic experience so much three years ago at Seoul that she is back with a U.S. team, this time as player-coach. A winner of 21 Grand Slam titles in doubles, she is staying in the village alongside the archers, bowlers, roller skaters and other less-renowned athletes.

--Track and Field. Most of the best U.S. athletes are preparing for the World Championships that begin later this month at Tokyo, but high jumper Hollis Conway, the national champion and the American record-holder, decided to fly south first to meet Cuba’s Javier Sotomayor, the only man to clear 8 feet.