ROME, AUG. 29 -- The world track and field championships opened today in a burst of medieval pageantry, gold medals for marathoner Rosa Mota of Portugal, shot putter Werner Guenther of Switzerland and distance runner Paul Kipkoech of Kenya and a disappointment for U.S. 100-meter champion Mark Witherspoon.

Mota's 2 hours 25 minutes 17 seconds became the fifth-fastest women's marathon in history. Guenther upset world-record holder and 1984 Olympic champion Alessandro Andrei of Italy with a throw of 72 feet 11 1/4 inches on his sixth try, with John Brenner of the United States third (71-4 1/4 to Andrei's 71-9 1/2). Kipkoech also beat an Italian favorite, Francesco Panetta, in 27:38.63 in a 10,000-meter race that ended in confusion.

Carl Lewis and Ben Johnson easily qualified for a much anticipated matchup in Sunday's 100-meter final, but Witherspoon failed to survive the first round of qualifying. Still bothered by a sciatic nerve injury he suffered at the Pan American Games, Witherspoon finished fifth in his heat in 10.65.

The first four finishers in each heat, plus the next four fastest times, qualified for today's second round.

Witherspoon had won the U.S. title in 10.04, a personal best, at San Jose, Calif., June 27. After his failure today, he said he felt a twinge in his right hamstring, but that was not the major problem. "I wasn't ready," he said. "I needed a race under my belt. I felt good, but I didn't go. I knew I didn't make it. I was scared."

His compatriot Lewis, trying to duplicate his 1983 triple in the only prior world championships, eased to victory in a meet-record 10.05 in the first round, equaling his best time of the season. He ran a 10.38 in winning his second heat.

"Tomorrow!" Lewis shouted when he finished.

"It was easy," Lewis said later. "I felt good and I ran very easy."

Canada's Johnson, who has a four-race winning streak over Lewis the past two years, advanced with a second-heat time of 10.14, even though he was nipped by Jamaica's Ray Stewart. He won his first heat in 10.24.

Pan Am Games champion Lee McRae of the United States also qualified for the final.

The 100-meter trials were the first events today at Foro Olimpico. By night's end, these championships could look back on a rocky start because of officiating confusion in the day's two main events -- the women's marathon and the men's 10,000 meters.

To the obvious ire of team officials and many of the 65,000 fans in the stadium, meet officials botched the endings of both races.

First they failed to tell the exhausted women winding up their 26-mile 365-yard marathon through the streets of Rome and into the stadium when they had finished their last lap around the track, so that many did not know when they had actually crossed the finish line. Some even tried to run an extra lap. Even Mota ran an extra 30 yards before realizing she had finished.

Zoja Ivanova of the Soviet Union was second in 2:32:37, France's Jocelyne Villeton third in 2:33:18.

In the men's 10,000 final that followed immediately, the officials somehow turned off the sign that ticks off the runners' remaining laps after Kipkoech crossed the line. Many racers who still had a lap to go quit, thinking the race was over, including Finland's Matti Vainio, who seemed headed for a bronze medal.

"It was sheer bush league," said one irate team manager who asked not to be quoted by name, "This is the sort of thing you might expect in a high school meet somewhere, not a world championship."

When the obviously oblivious officials marched off the track in a neat file after the confused ending, each carrying his folding chair, they were roundly booed by the mostly Italian crowd. As of 10 p.m. there was still great confusion about final placings in the 10,000.

Despite the botch-up, there was little doubt about the winner being Kipkoech, who led from the beginning, ran the last 5,000 in a swift 13:25 and finished 10 seconds ahead of Panetta.

Vainio appeared to be running third, but after officials turned off the lap number sign he slacked off and was overtaken by East Germany's Hans Joerg Kunz, who was awarded the bronze.

Besides the 100 finals, the second day of the nine-day meet includes the women's high jump final, in which Texas' Louise Ritter and Coleen Sommer will try to beat world-record holder Stefka Kostadinova of Bulgaria and a host of other top Eastern Bloc jumpers. The other finals will be the men's javelin and the men's 20-kilometer walk.

In the women's 100-meter trials, East German Heike Drechsler, trying for the same triple as Lewis -- 100, long jump and 400 relay -- reached the women's sprint semifinal with two easy victories.

Kostadinova and 11 others reached the women's high jump final by clearing 6-3 1/4. Among those advancing was defending champion Tamara Bykova of the Soviet Union.

Czechoslovakia's Jarmila Kratochvilova, 1983 world champion in the women's 400 and 800 meters who recently came out of retirement, eased into Sunday's semifinals of the metric half-mile. She was third in her heat in 2:03.06, behind Slobodanka Colovic of Yugoslavia (2:02.54) and Delisa Walton Floyd of the United States (2:02.76).

Soviet Maria Pinigina had the fastest time, 51.38, in the opening heats of the women's 400.

There were few surprises in the first round of the men's 800, except the absence of Brazil's Joaquim Cruz, the 1984 Olympic champion. Cruz skipped the 800 to prepare for the 1,500. Among the six heat winners was Johnny Gray of the United States (1:46.53).

In the women's 3,000 semifinals, Canada's Debbie Bowker took one heat in 8:46.88 and Britain's Wendy Sly another in 8:44.79. Romania's Maricica Puica, the 1984 Olympic champion, finished fifth in her heat and qualified for the final, but she limped off the track bleeding after apparently being spiked.