Given the somewhat strained feelings that have arisen during the run of the Olympic Games between the host country and the USA, it came as no surprise that every seat in the Chamshil Students Gymnasium was full at 10 a.m. Saturday morning.

Tickets to the first day of the boxing finals were a hot item. Included as the last bout on the morning's six-fight card was a heavyweight gold-medal bout between, you guessed it, a Korean, named Hyun-man Baik of Seoul, and an American,named Ray Mercer of Jacksonville, Fla.East was East and West was West and they were meeting in the ring at almost exactly high noon.

This had precisely the ingredients great fights are noted for. The promotersof the world had to be tearing their hair out. They knew this fight had potential. They knew this fight shouldn't be held until they had six months of lead time to milk the media and build the tension even higher, not to mention the gate. And it should be staged in Madison Square Garden or Caesar's Palace or Atlantic City or maybe Nairobi.

But if the Olympics are going professional, they're not going that professional.

Olympic rules stood: three three-minute rounds, and no betting line in Vegas.

The purse: whatever a gold medal and a silver medal cost these days.

For whatever reasons, the South Koreans and Americans have had a rather tumultuous Olympics together. Early in the Games, the Koreans reacted sensitively to coverage by NBC of a temper tantrum staged by a losing Korean _ a boxer, no less _ and that seemed to kick it off.

The NBC coverage _ no more extensive or one-sided than, say, typical coverage of Bobby Knight throwing a chair _ was seen around Korea, courtesy of the Armed Forces Network, and officials of the Seoul Olympic Organizing Committee were particularly dis traught, thinking that the world's largest garden party they were throwing had been tainted.

So it escalated from there, with editorials and newscasts questioning the Americans' ability to behave properly. Film clips were shown of the U.S. team's rowdy behavior at the opening ceremonies. The term "Ugly American" was tossed around a lot.

Not that there should be any impression that things got even close to out-of-hand. Korean spectators at the track were still wearing sun-visors that said "Pizza Hut." Cute little Korean kids were still smiling and saying "hello," they were still accepting dollars at the Reebok stores in It'aewon, and no one was rushing up to the DMZ to tell the 45,000 American troops there that they could go on home now.

But, still, there was enough bad blood to turn the Chamshil Gymnasium, when it was time for Baik and Mercer to mix it up, into, by Korean standards, a raucous atmosphere.

"In the red corner, from the United States of America . . ." said the announcer, and there were boos all around, like this was the Salt Palace and they'd just announced Akeem Olajuwon.

Three large Americans, wearing caps that said "Nothing Runs Like a Deere," stood up amidst a sea of black hair and gave the thumbs-down sign.

This was better than any of the Rocky movies except maybe the first one.

"In the blue corner, from the Republic of Korea . . ."

The place went berserk. Baik, who weighs 201 pounds and is therefore larger than 99.9 percent of his countrymen, did a kind of Hulk Hogan routine as his name was announced.

Then the American fans _ who were in the minority but still were well-represented _ seized a break in the din and started chanting "U.S.A.," "U.S.A."

They were soon drowned out, first by chants of "Hyun-man Baik," "Hyun-man Baik," and then by a simpler chant of "Zwissha," "Zwissha," which, according to a Korean usher wearing an "I Speak English" badge, translated into American means "Wow," "Wow."

Amid this commotion in the stands, the fight began. Both fighters rushed at each other. The brawl was on. Few punches landed, emotion overruling the basics of pugilism. And it appeared that Baik, a southpaw, was confusing Mercer, a straightforward puncher noted more for winning fights with knockouts, not points.

The tension heightened as the round wore on and then, out of nowhere, came this long right arm, attached to Mercer, that hit Baik flush on the jaw.

A left soon followed.

Baik hit the canvas of his home arena. The referee asked him if he knew what country he was in. He was stumped for an answer.

So the fight was stopped, Mercer went into a gold-medal high-five jive routine, the American fans waved their flags, the three guys in the "Nothing Runs Like a Deere" hats gave the thumbs-up sign, and the Korean fans quietly sat down.

The fight was over, that much was obvious. And the ending had been quite civilized. Everyone knew when to quit.