Beijing - Ethiopian wonder Tirunesh Dibaba completed her collection of big titles with the elusive 10,000m gold at the Beijing Olympics on Friday while Usain Bolt and Asafa Powell underlined their bid for a first Jamaican 100 metres gold.

Dibaba, by contrast, used her famous kick in the final lap to get gold after 5,000m bronze in 2004 with the second best time in 10,000m history, 29 minutes 54.66 seconds. Turkey's Elvan Ebeylegesse, an Ethiopian-born runner, also broke the magic barrier with 29:56.34 minutes.

Aged just 22, Dibaba has 5,000m world titles from 2003 and 2005, and 10,000 crowns from 2005 and 2007.

The first gold in the showcase sport went to Polish shot putter Tomasz Majewski, who emulated the 1972 glory of his role model Wladyslaw Komar.

In the 100m, the world record holder Bolt had enough shortly after the halfway mark of his second-round race, looked left and right and eased up. He still led all times with 9.92 seconds.

"I just ran the first 50 metres ... I am ready for my best, I think I did well," said Bolt.

The former world record holder Powell clocked 10.02 without giving it all, while the world champion Gay only came second in his race with an unimpressive 10,09 seconds.

So Gay had to explain himself to reporters while Bolt and Powell walked through the mixed zone chatting more or less only to one another after having done most of the talking on the track.

"My leg was OK," Gay said in reference to a recent hamstring problem at the US trials which cost him an Olympic berth in the 200m where he is also the world champion.

"I just took it easy. I felt good and relaxed, just wanted to make the next round."

Gay has the experience of a major title and ran a personal best 9.77 seconds this year. But he was beaten fair and square on May 31 in New York when Bolt stormed through in world record 9.72 seconds. Powell's former world record is 9.74.

It adds to the flavour of Saturday's semi-finals and final that Jamaica has never won the blue riband sprint at the Olympics.

Dibaba, meanwhile lived to her "destroyer" image on the last lap as she stormed past Abeylegesse in a remarkably fast race on a warm night under full moon in the National stadium.

The two runners were on their own in the last for the last four laps as they became the the only athletes besides China's world record holder Wang Junxia (29:31.78 in 1993) to break the magoic barrier.

Shalane Flanagan took the bronze for the US in 30:22.22 minutes.

Majewski, 26, came up with a huge personal best 21.51 metres in his fourth attempt to grab gold in impressive style. Komar was the only other Pole to win this discipline at the Olympics, 1972 in Munich.

World indoor champion Christian Cantwell salvaged silver for the US with 21.09m in his final attempt. Former world champion Andrei Mihknevich of Belarus took bronze with 21.05m.

US ace Adam Nelson failed again to get a first Olympic gold, out early after fouling all three attempts. The 2004 Olympic champ Yuriy Bilonog of Ukraine managed only sixth.

In preliminary action, the 2005 world champion over 800m and 1,500m Rashid Ramzi led 1,500m qualifying in 3 minutes 32.89 seconds, a result that drew a loud "wow" out of reigning world champion Bernard Lagat of the US who had watched the race after his heat.

"I want to win. I wanted to make sure of a good position but it wasn't good at the bell. I have to avoid this in the semis. But I was confident I would get out," said Lagat, who won bronze and silver for Kenya 2000 and 2004 before getting a rare 1,500m and 5,000m double at the 2007 worlds for the US.

World record holder Gulnara Galkina-Samitova led the way into the inaugural women's Olympic 3,000m steeplechase final, with former world champion Bershawn Jackson and fellow-American 2000 Olympic champion Angelo Taylor through to the next round in the 400m hurdles.

US champion Hyleas Fountain led the overnight heptahlon ranks with 4,060 points from Ukraine's Natalia Dobrynska (3,996) and British hope Kelly Sotherton (3,938). Sweden's Carolina Kluft, who won this event at all big meets 2002-2007, no longer competes in heptathlon.

Saturday's medal events apart from the 100m are the men's 20km race walk and the women's shot put.