[3] Watanabe won the Philippines' first gold medal at the Asian Youth Judo Championship during the tournaments 2014 edition held in December 13–14 in Hong Kong.

[4] On February 12, 2017 at the Grand Slam Paris, Watanabe won a bronze medal after defeating Lucy Renshall of the United Kingdom in the under 63 kilogram event.

[10] She later settled for silver after losing to Austrian Kathrin Unterwurzacher in the final of the same category at the 2017 European Women's Open Tournament in Austria.

[11] The Philippines' first silver medal at the 2018 Asian Games was from Watanabe who lost to Nami Nabekura of Japan in the women's -63 kg final.

[13] Competing in the Women's −63 kg, Watanabe failed to progress beyond the Round of 32 since she was eliminated via an ippon by Cristina Cabaña of Spain.