Reigning world champion Tamyra Mensah-Stock stormed into the semi-finals of the women's wrestling competition with consummate ease on Monday, winning both her matches by technical superiority on her Olympic debut without dropping a point.

The United States' Mensah-Stock took just over two minutes to overpower 2016 Olympic champion Sara Dosho of Japan in a 10-0 shutout in her first match before turning in an equally dominant performance against China's Feng Zhou in the quarter-final.

Dosho was dispatched in a blur of lightning quick takedowns and ankle laces that the Japanese wrestler had no answer to, leaving her shattered.

"I'm so disappointed with myself because I couldn't deal with my opponent's tackles many times. I'm stronger than what I used to be," Dosho, 26, said.

"I really wanted to get the gold medal. I know she is so strong and I wanted to guard against her tackles, but I couldn't do so."

The 28-year-old Mensah-Stock then turned her attention to Feng, gaining a two-point advantage barely seconds into the match and followed that up with two double leg takedowns to lead 6-0 at the break.

Four more technical points followed in quick succession and Mensah-Stock earned a 10-0 victory despite Feng mounting a desperate defence, setting up a semi-final clash with Ukraine's 2018 world champion Alla Cherkasova.

In the men's Greco Roman welterweight category, Armenia's Karapet Chalyan marched into the semi-finals with a 5-0 victory by points over Uzbek Jalgasbay Berdimuratov and a narrow 2-1 win over the Russian Olympic Committee's Aleksandr Chekhirkin.

Chalyan, a bronze medallist at last year's European Wrestling Championships, will be up against Kyrgyzstan's former Asian champion Akzhol Makhmudov who impressed with 11-0 and 9-1 victories in his two bouts.

ROC's Musa Evloev and Armenia's Artur Aleksanyan -- two favourites for gold in the Greco Roman heavyweight category -- also qualified for the semi-finals.