BEIJING — Jamaicans proved they are the world's fastest humans Sunday when Shelly-Ann Fraser won the women's 100 meters at the Olympics on the heels of Usain Bolt's record-setting victory.

Fraser led a unique Jamaican triple, already celebrating with her fist pumping the air as she crossed the line with two teammates in canary yellow in her slipstream.

Fraser finished in a season-leading 10.78 seconds, with Sherone Simpson and Kerron Stewart sharing silver with in 10.98.

"It's wonderful. Top 3 for Jamaica — history," Simpson said. "This says a lot for our country."

In the battle of sprinting powers it was Jamaica 2, USA 0 after the 100s, and 4-1 overall in the medal count. It was stunning domination.

Lauryn Williams was the first American in fourth place in 11.03, with Muna Lee a disappointing fifth.

As extensive a tradition of stellar sprinting as Jamaica has, the Caribbean island of about 2.8 million people never had won an Olympic gold in the 100 until this weekend.

Minutes earlier, Gulnara Galkina-Samitova set the second world record in as many days at the Olympic track, running the first sub-nine minute steeplechase in history to take the gold medal.

The Russian steadily stretched the field with her long, elegant stride until she was all alone and only had the clock to beat.

She did so, too, improving her own world record to 8 minutes, 58.81 seconds amid the cheers of the 91,000 fans at the Bird's Nest.

While Bolt's 100 record came in the most fabled event, Galkina-Samitova got hers in the Olympic debut of the 3,000-meter steeplechase.

Eunice Jepkorir of Kenya took silver, almost nine seconds back, edging another Russian, Ekaterina Volkova, in a sprint finish.

The women's steeplechase made its debut at the world championships in 2005 and Russians have dominated the early years.

In the 1,500, world champion Bernard Lagat was eliminated in the semifinals, finishing sixth in his race with only five getting a guaranteed spot. On best time, he missed out by .02 seconds.

Lagat was chasing a 1,500-5,000 double but now only has his least favorite event left to make amends.

"I ran hard. Hey, that's life," Lagat said. "I'm going to concentrate on the 5. I'm not going to cry."

After a 7 a.m. start, a 38-year-old mother Constantina Tomescu-Dita of Romania won the first gold of the day. She beat reigning world champion and pre-race favorite Catherine Ndereba of Kenya to win a marathon that started at Tiananmen Square and never faced the haze of the city's notorious pollution.

The day would be capped at the buzzing Bird's Nest, where two of the greatest African long-distance runners were to face off in the 10,000 meters — veteran Haile Gebrselassie against Ethiopian compatriot Kenenisa Bekele.

Primoz Kozmus won Slovenia's first athletics gold medal in Olympic history, taking the hammer throw with his season's best throw of 82.02. He edged two Belorussians.

Vadim Devyatovskiy, who was fourth at the 2004 Athens Olympics, took silver this time with 81.61. Three-time world champion Ivan Tsikhan won bronze with 81.51.

Other finals during the busy evening program included the women's triple jump.

Casting an early pall, however, reigning women's 400-meter hurdles champion Fani Halkia of Greece tested positive for a banned drug and will not defend her title.

The International Olympic Committee confirmed Sunday that Halkia tested positive for a steroid at a Greek athletics team training camp in Japan before coming to Beijing.

She was the second track athlete to test positive during the IOC's Beijing anti-doping program, after the IAAF had made special efforts to catch as many as possible before competition starts. On Saturday, the Bulgarians announced that middle-distance runner Daniela Yordanova had withdrawn after testing positive for testosterone.

There was also bad news from Liu Xiang, China's biggest track star. The defending champion in the 110 hurdles is still suffering pain from an inflamed hamstring.

Ahead of Monday's opening heats, Liu has been training in seclusion for weeks amid questions about his fitness. Liu has competed rarely this year and in June saw his world record fall to Dayron Robles of Cuba.

Overall, though, the stories of gold-silver-bronze still dominate.

After months of trepidation that pollution would be a major factor during the marathon, Sunday's weather proved it was not.

"The weather helped me a lot," said Tomescu-Dita, the 2005 world championship bronze medalist. "I'm very happy because it's not very, very hot," she said of the 23 degrees Celsius (73 degrees F) conditions.

Tomescu-Dita won in 2 hours, 26 minutes, 44 seconds and held an edge of 22 seconds over Ndereba, who edged home favorite Zhou Chunxiu by a second.

Despite the disappointment of losing silver, Zhou produced the first medal for China in the track program.

For world record-holder Paula Radcliffe, there was only disappointment. The Briton decided to race in her fourth straight Olympics only earlier this week because of a stress fracture in her thigh.

It was all in vain. She finished 23rd, nearly six minutes behind the winner and even had to resort to walking near the end of the race. At a railing, she stretched to soothe pain in her foot before resuming her race.

She kept running only because, "it's horrible when you have to drop out."

In contrast, it seems nothing can go wrong for Bolt.

After his world record of 9.69, cutting his earlier mark by .03 seconds, he is now looking for a golden triple.

On Monday, he goes into the heats of his favorite event — the 200. Speculation is no longer on whether he will win, but whether he will beat the 12-year-old world record of 19.32 that Michael Johnson set at the 1996 Atlanta Games.

Next weekend, he will anchor Jamaica's 4x100 squad, hoping to beat the Americans again.