TOKYO (REUTERS) - Japanese Prime Minister Yoshihide Suga on Sunday (July 25) phoned judoka Naohisa Takato to offer congratulations after the triple world champion secured the host nation's first gold medal as the Games heat up in Tokyo.

Takato's victory over Taiwan's Yang Yung-wei on Saturday offers organisers hope of improving enthusiasm for the delayed Olympics among the Japanese public, who are labouring under a state of emergency in the capital amid elevated Covid-19 cases.

The hosts added another in the pool on Sunday, with Yui Ohashi claiming the women's 400m medley in a time of 4min 32.08sec.

Attention also turns to tennis player Naomi Osaka, who on Friday lit the Olympic cauldron at the opening ceremony, in her opening match against China's Saisai Zheng at the Ariake Tennis Park.