Naohisa Takato of Japan overcame Georgia's Robert Mshvidobadze in a repeat of the World Championships final to secure the under-60 kilograms gold medal at the International Judo Federation Grand Prix in Montreal.
Takato again got the better of his arch-rival as the world champion claimed victory by ippon in the bout for gold at Maurice Richard Arena.
Adonis Diaz of the United States and South Korea's Lee Ha-rim were the recipients of the bronze medals in the division.
Takato was one of two Japanese gold medallists on the opening day as 18-year-old Wakana Koga topped the podium in the women's under-48kg category.
Koga defeated Olympic champion Paula Pareto of Argentina en route to the final, where she ousted Portugal's Catarina Costa to take gold.
Pareto recovered from her semi-final exit to seal bronze alongside Shira Rishony of Israel, who sealed her ninth Grand Prix medal by finishing joint third.
Israel had a gold medal to celebrate later in the day when Gefen Primo defeated American Angelica Delgado to clinch the women's under-52kg crown.
Primo was joined on the podium by bronze medallists Sarah Menezes of Brazil, the London 2012 Olympic champion, and Rio 2016 silver medallist Jeong Bok-yeong.
Christa Deguchi triumphed in an all-Canadian under-57kg women's final as she was too strong for compatriot and Osaka Grand Slam winner Jessica Klimkait.
Deguchi emerged victorious from a thrilling contest as she got Klimkait in an inescapable shime-waza.
Timna Nelson Levy added another medal to Israel's tally with bronze alongside Poland's Julia Kowalczyk.
Kherlen Ganbold of Mongolia claimed his third Grand Prix title as he beat Belgium's Kenneth Van Gansbeke in the men's under-66kg final.
Canada's Jacob Valois and Ireland's Nathon Burns did enough for bronze.
The event is due to continue tomorrow.
Watch all the action on Judo TV.