Angus took an hour to beat Japan’s Kenta Nishimoto, 16-21 21-13 21-12 to claim the title – his first since winning the Malaysia Masters in January 2017.
The third seed beat three Chinese on the way – Lin Dan in the opening round, Youth Olympic Games champion Li Shi Feng in the second, and second seed Shi Yu Qi in the semifinals.
Three-time world junior champion Kunlavut Vitidsarn created some ripples at the event, reaching the semifinals, which he lost to Nishimoto. Vitidsarn beat Vladimir Malkov in the opening round, followed by Soong Joo Ven and compatriot Suppanyu Avihingsanon.
Yamaguchi had a tough semifinal, in which she overcame Carolina Marin 14-21 23-21 21-18.
The Malaysians started with the upset of third seeds Choi Solgyu/Seo Seung Jae and went on to beat Ou Xuan Yi/Zhang Nan, Takuro Hoki/Yugo Kobayashi and Lee Jhe-Huei/Yang Po-Hsuan.
England’s Marcus Ellis/Lauren Smith captured the mixed doubles crown beating Indonesia’s Hafiz Faizal/Gloria Emanuelle Widjaja 21-16 13-21 21-16. The England duo had earlier won a thriller in their semifinals against Goh Soon Huat/Shevon Lai Jemie 19-21 21-19 24-22.