Rio 2016: Matej Toth wins men's 50km walk

Matej Toth added Olympic gold to his World Championship title by taking victory in a gruelling men's 50 kilometre walk race on Friday, while Liu Hong won a thrilling women's 20km contest.

Slovakian Toth, champion in Beijing at the Worlds 12 months ago, was trailing Australia's Jared Tallent with approximately 5km remaining.

However, Toth pushed on strong to come home in a time of three hours, 40 minutes and 58 seconds, 18 seconds ahead of Tallent.

"Today was very tough. I can't compare [it] with Beijing last year. It was one of the easiest 50 kilometres," Toth said.

"This was one of the hardest. So it was very tough. It was very warm. Also in Beijing it was warm but I think this was much, much harder."

Hiroaki Arai finished third to complete the podium but was then disqualified following a collision with Canada's Evan Dunfee, however he was subsequently reinstated on appeal to claim bronze.

Meanwhile, France's Yohann Diniz - the world record holder - finished a valiant eighth despite soiling himself in the early stages and collapsing in the searing heat after 35km.

Several athletes were treated at the finish line with competitors pouring water and ice over their heads to cool down in the soaring temperatures.

In the women's 20km, Liu clinched the gold medal for China after an intense battle with Mexico's Maria Gonzalez.

The two led for the majority of the race and it was Gonzalez who held the advantage going into the final kilometre.

But Liu - the current World Champion and world record holder - lived up to her billing as favourite by finding the extra gear to win by a mere 0.02 seconds.

China's Lu Xiuzhi was just 0.07secs adrift and earned the bronze medal.