BARCELONA ’92 OLYMPICS / DAY 7 : Oncins, Ranked No. 53, Upsets Chang : Tennis: Sixth-seeded American loses on a day during which he has pain in his stomach.

Michael Chang’s Olympic experience died here Friday in the second round. It came to rest in a clay court graveyard of sorts, the back forty of a massive tennis complex, the kind of place where so many players of lesser esteem come and go quietly.

Chang, the never-quit player who was seeded sixth here, did not go quietly. But he did go, 6-2, 3-6, 6-3, 6-3, at the hands of Brazilian Jaime Oncins, unseeded and ranked No. 53 in the world, 47 spots worse than Chang. And even though Oncins is a difficult competitor to handle--he ousted Ivan Lendl in five sets in this year’s French Open--this kind of end to a quest for an Olympic medal did not sit well with Chang.

“This is kind of disappointing, because I trained hard and worked hard for it,” he said. “I rearranged my schedule to do the things you need to do, and I had some pretty good clay-court matches leading up to this. But sometimes, things just don’t work out the way you want them to.”

Part of the problem, Chang said, was a sour stomach that got worse as the match went along.

“I was fine when I went out there,” he said, “but near the end of the second set, it started to really hurt and it would especially bother me after a long point.”

But Chang was also careful to point out that Oncins played well, deserved to win and probably would have, even if Chang felt fine. Chang also said he had no complaint about where he played, on the No. 2 show court, which can be a crazy and difficult place in a situation such as the one Chang faced Friday.

The complex here is terraced, and Court 2 is on the bottom tier. From the top of the huge high-rise stands surrounding center court on the top terrace, to the bottom level, where Court 2 rests, is about the height of a 12-story building. All the noise, wind, dust and bizarre tennis fans seem to flow downhill, toward Court 2.

It was there that Chang--the 1989 French Open champion, a real gold-medal possibility and always of strong mind and body no matter who or where he is playing--had to put his Olympic dream on the line.

The stands on one side could accommodate perhaps 500 but held, for this match, perhaps 600. Of those, 40 or so were both loud of color--dressed in bright yellow Brazilian team shirts--and of vocal cords. They shouted and stomped with each positive moment achieved by Oncins, and while they weren’t reaching the disruptive levels of a Paraguay Davis Cup crowd, they gave it their best. At one stage, on a point that wasn’t even crucial, Chang netted a second serve from Oncins, and the Brazilian partisans stomped and shouted for 30 seconds.

In addition, this was the only match going on at the time that had any appeal whatsoever. On center court, Chang’s American teammate, Pete Sampras, was dismantling another Jaime, Yzaga from Peru, 6-3, 6-0, 3-6, 6-1, and so the Chang-Oncins match was the place to be.

At every break, more fans squeezed and pushed into the seats, and it took longer and longer to quiet the fans to allow play to continue. Every time one of the players was ready to make a service toss, a voice from an umpire’s chair somewhere up the hill boomed out, while on the street adjacent to the court and across from the packed, noisy stands, there flowed a steady stream of loud buses, belching smelly fumes.

It was so hot and dusty that they thoroughly hosed the court after the third set, and it dried in plenty of time for the players to come right out and play without additional delay.

The place had multiple distractions. It was a little like playing tennis on the straightaway at the Indy 500. Had this been John McEnroe playing, rather than the more composed Michael Chang, Olympic tennis would have had its first serious international incident.

All this, and Chang had a stomachache. Also, Oncins, a lanky 6-foot-4 player with a huge serve and an erratic ground-stroke game, was playing like a man possessed.

“This is just the kind of player who gives Michael trouble,” American Coach Tom Gorman said while watching Chang struggle late in the third set. “This guy is streaky.”

This time, Oncins’ streak lasted four sets. He matched Chang from the baseline and outshined him at the net. Chang’s best chance to turn the match around was with Oncins serving at 5-3 of the third set and the match at a set apiece. Oncins double faulted badly at love-30, giving Chang three break points to get back on serve. So frustrated with himself was the Brazilian that he whacked two tennis balls into the back screen before serving again.

But Oncins calmed himself, saved all the break points and served out the set with an ace down the middle.

“What’s funny is, I feel good about my game,” Chang said afterward. “I feel like I’m playing some of my best tennis ever. I still believe all the hard work will pay off, even if it is six months down the line.”

Indeed, what Chang admitted to suffering was a pain in his stomach, but what he had experienced overall was in a different area of his anatomy.