The 22-year-old came out on top against Russian opponent Irina Dolgova, who was looking for a title on home soil to add to her Abu Dhabi Grand Slam win in October.

The final was a close contest and, as there was nothing to separate them in regulation time, an additional five minutes and golden score were required to decide the winner.

By this stage, Dolgova was visibly tired, allowing Tonaki to catch her on the ground with a kesa-gatame hold, causing the home judoka to tap out after five seconds.

The bronze medals went to Mongolia’s Bokyeong Jeong, who defeated 2011 World Judo Masters bronze medalist Eva Csernociczki of Hungary by a waza-ari, and Urantsetseg Munkhbat of Mongolia, who won against Brazilian Arissa Koyama.

However, there was to be gold for Russia in the under-52kg women's division with Rio 2016 Olympic bronze medallist Natalia Kuziutina beating Amadine Buchard of the United States in the final.

This was Kuziutina's third Masters medal having won silver a year ago and gold the previous year.

The bronze medals went to Romania's Alexandra-Larisa Florian and Brazil's Erika Miranda.

The women's under-57kg category saw Rio 2016 Olympic silver medalist Sumiya Dorjsuren of Mongolia win a record fourth World Judo Masters title as she triumphed against Japan’s Tsukasa Yoshida, who had beaten her in the World Championship final in Budapest in September.

The bronze medals were claimed by France’s Helene Receveaux and Youjeong Kwon of South Korea.

It was not a day to remember for Olympic champion Rafaela Silva of Brazil who could only finish fifth.

The women's under-63kg category also saw an athlete claim an additional Masters title as Japan's Miku Tashiro, the Tokyo Grand Slam winner, beat compatriot Nami Nabekura in the final to claim her third gold.

Twenty-three-year-old Tashiro emerged victorious after just 43 seconds of the golden score with an excellent uchi-mata.

World champion Clarisse Agbegnenou of France took home a bronze medal along with Russia's Daria Davydova.

The under-60kg category of the men’s event also saw a Japanese gold medalist with Ryuju Nagayama winning his first-ever World Judo Masters title.

The world number nine defeated Spain's Fracisco Garrigos with an ippon seoi-nage after just one minute.

Mongolia's Amartuvshin Dashdavaa won bronze alongside Sharafuddin Lutfillaev of Uzbekistan, who also won bronze at the Abu Dhabi Grand Slam in October.

Kherlen Ganbold claimed another medal for Mongolia in Saint Petersburg. 

This time it was in the men's under-66kg category, as Ganbold beat Asian Championships silver medalist Yeldos Zhumakanov of Kazakhstan to take gold.

Ganbold, who won the 2013 Grand Prix in Miami, managed to defeat Zhumakanov with just seven seconds left in regulation time by luring the Kazakh towards him and lifting him up and over for ippon.

Georgia's Vazha Margelashvili defeated three-time world silver medalist Mikhail Puliaev of Russia to take the first bronze before Israel's Baruch Shmailov took the second with victory over Brazil's Charles Chibana.

The heaviest category of the day, the under-73kg men's, saw world champion Soichi Hashimoto of Japan retain his Masters title with victory over London 2012 Olympic champion Lasha Shavdatuashvili from Georgia by a waza-ari score, which came from an osoto-gari.

Hashimoto's win ensures he will finish the year as world number one.

The bronze medals in that category were won by Azerbaijan's Hidaya Heydarov and Sweden's Tommy Macias respectively.

The event continues tomorrow with titles in the women's under-70kg, under-78kg and over-78kg to be decided along with the men's under-81kg, under-90kg, under-100kg and over-100kg.

Only the top 16 in each weight category are invited to the prestigious end-of-season event.

Watch all the latest judo action on Judo TV.