Matej Toth became the first Slovakian to claim a World Championships gold medal on Saturday, taking out the men's 50-kilometre walk.

Toth dominated his event in Beijing, entering the Bird's Nest with a Slovakian flag draped over his shoulders, while in the 4x100 metre relays, Jamaica continued their sprinting supremacy.

Jamaica's Sherone Simpson, Natasha Morrison, Kerron Stewart and recently crowned 100m champion Shelly-Ann Fraser-Pryce dominated heat one of the women's 4x100m to win in 41.84 seconds.

United States, Trinidad and Tobago, Netherlands, Great Britain, Canada, Germany and Russia also advanced.

In the men's event, Jamaica rested Usain Bolt but still ran fastest in the heats, winning the second in 37.41secs, while USA (37.91secs) claimed the first.

Great Britain, Germany, France, China, Antigua and Barbuda and Canada also progressed.

Toth, who had never previously claimed a medal at an Olympic Games or World Championships, won by 1:45 from Australia's Jared Tallent (3:42:17), while Takayuki Tanii of Japan (3:42:55) claimed bronze.

Tallent added another silver medal to his collection, having finished second at the past two Olympics in the 50km walk.

Having finished second at last year's European Championships, Toth was given a boost in the lead up to Beijing 2015 when his conqueror in Zurich - France's Yohann Diniz - withdrew through injury, and the 32-year-old seemed desperate to take advantage.

Toth took control of the race early, surging away in the opening kilometres and holding his advantage throughout, even after a toilet break.

Defending champion Robert Heffernan of Republic of Ireland finished fifth with a time of 3:44:17.

In the 4x400m relay heats, defending champions USA notched the fastest time for the men, stopping the clock at 2:58.13 in the second heat, while Great Britain (2:59.05) won the first.

Belgium, France, Russia, Trinidad and Tobago, Jamaica and Cuba also qualified for the men's final.

USA also set the fastest time in the women's 4x400m, posting 3:23.05 to win the second heat, while Nigeria (3:23.27) surprisingly overcame Jamaica and Russia in heat one.

Canada also advanced from the first heat, while Great Britain, France and Ukraine complete the final.

USA's Ashton Eaton continued his run towards decathlon gold, claiming second in the 110m hurdles, 11th in the discus and fifth in the pole vault.

Canada's Damian Warner (13.63secs) kept the pressure on Eaton early by winning the hurdles, while Rico Freimuth of Germany (50.17m) prevailed in the discus and Belgium's Thomas van der Plaetsen (5.30m) won the pole vault.

With two events remaining, Eaton has 7423 points and could still overhaul his own world record of 9039 points.

Warner (7169) remains second, while Freimuth (7115) is third.