Overall, Jamaica could be looking at six golds in sprint events after Bolt and Shelly-Ann Fraser combined to sweep the 100s so far.

Bolt is overwhelming favorite in the 200 and Veronica Campbell-Brown wants to extend her title from 2004 before the weekend relays set up more U.S-Jamaican duels.

Usain Bolt of Jamaica gestures before his men's 200m heat of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games in this August 18, 2008 combination photo. [Agencies]

World and defending champion Jeremy Wariner and LaShawn Merritt kept on track for their golden clash in the 400, both easily going through into Tuesday's semifinal.

Both jogged home to win their heats.

"No surprise. He's ready, I'm ready," said Merritt.

"It's time for a showdown, a throwdown." The pair of US sprinters finished 1-2 at the 2007 world championships and own the year's two best times.

Wariner has said he intends to break the world record of 43.18 of Michael Johnson -- who now serves as his manager.

The 400 semifinals are on Tuesday, the final on Thursday.

Later Monday, Yelena Isinbayeva was the overwhelming favorite to defend her pole vault title despite this season's emergence of US rival Jenn Stuczynski.

And there were hopes that the Russian would get track a third world record in as many days at the games.

She improved already twice on her mark this season, bringing it to 5.04 meters.

 After Bolt improved his 100 record on Saturday, and Gulnara Galkina-Samitova rand the first sub-nine minute women's steeplechase in history on Sunday.

In the 800, the quarter century-old record could also be under threat when Kenya's two great front-runners, Pamela Jelimo and Janeth Jepkosgei, go head-to-head in the final, chased by 2000 Olympic champion Maria Mutola in her fifth and last final at the games.

Steeplechasers should make it a double-gold day for the east African nation, possibly sweeping the medals with Ezekiel Kemboi seeking to extend his title.

It would immediately heat up the race with Ethiopia, which won both the men and women's 10,000, for African domination.