Bronze went to American Helen Maroulis - a Rio 2016 champion at a lower weight - and Bulgaria's Evelina Nikolova.

World champion at 57kg and Rio 2016 champion up at 63kg, Kawai dominated the gold-medal bout to make it a family double little more than a day after sister Yukako had won gold in the 62kg.

"Being defending champion is nice, but what makes me happiest is a joint gold medal with my sister," Kawai said.

"I saw that wonderful match in front of me, I had no choice but to go for it. 

"Our family has her medal, I wanted to make sure we had another."

The United States' world champion David Taylor beat Iran's Rio 2016 gold medallist Hassan Yazdanicharati 4-3 to win the men's 86kg freestyle gold.

San Marino won its first-ever wrestling medal through Myles Nazem Amine, and Artur Naifonov of the Russian Olympic Committee (ROC) also won bronze. 

Taylor made his move in the closing seconds after being behind for much of the bout against his great rival Yazdanicharati

"I don’t want to talk about wins over this guy because he's helped me become a better wrestler," Taylor said.

"For wrestling fans around the world, that we could wrestle in a gold-medal match was pretty special. 

"We are both great representatives of the sport in the way that we carry ourselves and compete."

ROC's Zavur Uguev beat India’s Ravi Kumar Dahiya in the men’s 57kg freestyle final.

American Thomas Gilman and Nurislam Sanayev of Kazakhstan both took bronze.

"I was concentrating solely on my opponent, the match and the strategy<" Uguev later said.

"The match was very difficult. 

"During all these years, I’ve trained for and waited for this moment. 

"I did my best."