Sullen and silent Steve Ovett captured the first of his long-awaited duels against fellow Englishman Sebastian Coe, winning the Olympic gold medal today at Coe's best distance, 800 meters.

The race was decidedly unsatisfying, however, considering the great expectations it had aroused. No one knew what grand and electrifying things might happen when the world's two premier middle-distance runners lined up in the same race for the first time in two years with the Olympic torch blazing above them in Lenin Central Stadium.

As it turned out, there was little spectacular about it, except for the intensity of feelings and the fact that Ovett later typically declined to talk to the press, even with his first Olympic gold medal safely around his neck.

Ovett's winning time was 1:45.4, a full three seconds off Coe's world record for the distance. The race was exciting but much slower than anticipated, and tactically curious.

Ovett -- who has long contended that his objective in any foot race is to beat the other people in it, and not necessarily to set records -- ran pretty much the way he wanted to. Coe was strangely flat and, by his own account, unresponsive to the dynamics of a peculiar race.

Ovett, 24, twice fought himself out of awkwardly boxed positions, took the lead with about 80 meters to go, and sprinted home with the fabled finishing kick that has made him one of the world's most feared competitors at distances ranging from 800 meters to half-marathons.

Coe, 23, a more fluid and elegant stylist who often breaks open races early with a smooth burst of speed, started in Lane 8 and chose to run the whole race on the outside, away from the considerable jostling in the closely bunched field.

He was in the position he wanted, but he strangely failed to respond to the spurt of Soviet Nikolai Kirov early in the second lap. He lost the race right there when he failed to follow the leader.

"I didn't respond when the break was made at the front, that's where I threw it away," said the sloe-eyed and cerebral Coe, obviously downcast but still civil, more gracious as the silver medalist than Ovett was in is golden moment.

"It went into the race feeling that I was hopefully in a position to cover everything that was thrown at me. I failed in one vast, very important area. I just didn't cover what was going up front with anything like the king of speed, thought, or movement that was necessary."

Coe tried desperately to come from behind in the last 100 meters, but that is almost a mission impossible against the redoubtable Ovett. Coe's face was a portrait in futility and desperation as he passed Kirov but finished half a second behind Ovett in 1:45.9. The Russian took the bronze medal in 1:46.0. s

Ovett finished with his jaw jutting haughtily and his face wrapped in a self-satisfied expression that was half-smile and half-smirk. He now will be heavily favored on Friday to win the 1,500 meters, a distance at which he is undefeated since May, 1977.

Coe, who shares the 1,500-meter world record time of 3:32.1 with Ovett and holds the 800- and 1,000-meter world marks, was conceding nothing, however.He still looms between Ovett and the 800-1,500 Olympic double last achieved by New Zealand's great Peter Snell in 1964.

"We all live to fight other battles on other days," said Coe, determination and hunger for revenge mingled in his usually gentle voice.

Ovett undoubtedly was the most closely watched winner of the day as the controversial Moscow Games reached their halfway point, but there were others.

Great Britain's flamboyant Daley Thompson won the decathlon, a worthy successor to 1976 glamor guy Bruce Jenner in personality as well as athletic skill, and the Italian men's basketball team upset the Soviet Union, 87-85.

But there were more poignant losers today, who will not get another chance.

Alberto Mercado, the 19-year-old fly-weight who lost his job with the Puerto Rican Department of Parks and Recreation for leading Puetro Rico's battle to participate in Moscow despite the boycott, saw his dream of a gold medal go down the drain when he lost his opening about because of a cut. a

Mercado had been considered a threat to win the 112-pound boxing class, but his fight against Roman Gilberto of Mexico was stopped after a Gilberto butt opened a cut on Mercado's right eyelid.

Mercado, the Pan-American Games and World Cup champion in his weight class, cried after his heart-breaking mishap. "I knew I was going to win," he said. "Now this."

Another crestfallen loser was East German Marlies Gohr, who lost the women's 100-meter dash by a hundredth of a second to Lyudmila Kondratyeva, the workd record holder in the event (10.87 seconds). Many of the spectators at 103,000-seat Lenin Stadium thought Gohr hit the tape first but Kondratyeva was clocked in 11.06, Gohr in 11.07.

Meanwhild, Soviet fencer Vladmir Lapitsky, the reigning world champion in the foil, nearly lost more than a sporting contest when his Polish opponent broke his sword and accidentally ran it through Lapitsky's chest, narrowly missing his heart. Adam Robak of Poland and Lapitsky attacked simultaneously in their team match, and Robak's foil broke against the side of Lapitsky's mask. As Lapitsky turned to avoid a collision the broken weapon pierced the protective clothing on the back of Lapitsky's arm and came out through the frount of his chest.

There was no immediate word on Lapitsky's condition. A Soviet spokesman said the 21-year-old fencer's heart was not damaged, but "apparently a blood vessel has been injured." An international Fencing Federation doctor later said these were no signs of internal bleeding.

In a grueling but less dangerous sport, Thompson, a brash Briton who will be 22 next week, won the decathlon, but missed a splendid opportunity to erase Jenner's Olympic record of 8,617 points and the world record of 8,649 points set earlier this year by West German Guido Kratschmer, who is not here because of the boycott.

Thompson needed to run the 1,500 meters, last of the 10 events that are split over two days, in 4:22.6 to surpass Jenner -- now retired to pitching cameras, breakfast cereals and other goods instead of javelins and shot. Thompson needed a time of 4:17.2 to eclipse Kratschmer's record. But fatigued from the first nine events, Thompson finished last in the 1,500 meters in a slow-motion 4:39.9 Perhaps he should have eaten his Wheaties.

Other gold medals in track and field were won today by Sara Simeoni of Italy, whose high jump of 1.97 meters (6 feet-5 1/2) broke the Olympic record of 1.93 meters (6-4) set in 1976 by East German Rosemarie Ackermann, and by hurdler Volker Beck of East Germany. He took the 400-meter hurdles in a time of 48.70 that wouldn't have stood a chance if American Edwin Moses, West German Harold Schmidt and other boycotting hurdlers had been present.

Simeoni used the modern high jumping technique known as the "Fosbury Flop," after 1968 gold medalist Dick Fosbury, in contrast to the more orthodox straddle technique of Ackermann, who went out at 1.91 meters (6-3 1/2), then sat on the ground and cried. Simeoni came over and comforted the dethroned champion.

There was, predictably, no such scene after the men's 800 meters. Ovett and Coe, bitter rivals from the same country who have no particular fondness for one another, chatted briefly before the medals were presented, but it was strictly a courtesy.

Coe said later that he could not remember what Ovett had said to him. Asked what he had said to Ovett, he responded: "Obviously, congratulations."

And not much more.

The start of the race was closely clustered, Coe on the outside and Ovett boxed behind an East German and Frenchman Jose Marajo on the first lap.

The time after 400 meters was only 54.3, but early in the second lap Ovett looked hopelessly boxed again. He elbowed East Germany's defeat Wagenknecht to try to get free, and was hit back in turn, but he managed to escape.

Ovett did not wave to the crowd as he finished, a favored gesture that other runners find insufferably arrogant, and disdainful of the runners behind him. But he stopped shortly after the finish line, puffed out his chest and raised his arms triumphantly.