Liu Hong of China celebrates winning the gold medal with bronze medallist Lu Xiuzhi of China after the women's 20km race walk final in Rio de Janeiro, Brazil, August 19, 2016. [Photo/Agencies]

China's Liu Hong won women's 20km walk final on Friday, fending off Mexico's Maria Guadalupe Gonzalez in a thrilling final kilometre dash to the finish line to snatch gold.

World champion Liu was touted as the hot favourite heading into the Rio Games and she lived up to the billing, powering away from Gonzalez as the finish line came into sight to win in 1:28:35.

Gonzalez entered the final kilometre in the lead but she was powerless to stop Liu's late onslaught on a hot and humid day, crossing the line 0.02 seconds behind the 29-year-old world record holder.

China's Lu Xiuzhi, who won silver at last year's world championships, had to settle for bronze.