World No. 12 Sindhu triumphed 21-8 15-21 21-16 in a contest which lasted an hour and three minutes to make the summit clash of the USD 120,000 event.
The two-time World Championship bronze-medallist, who is seeded fifth here, Sindhu will next square off against the winner of the match between He Bingjiao of China and sixth-seeded Japanese Minatsu Mitani.
But Yamaguchi did not let the Indian run away with it and roared back into the contest to claim the second game. The World No. 9 went neck-and-neck with the Indian till 15-15 before breaking away to draw level.
Sindhu raised her tempo in the decisive third game and raced to an 11-5 lead. Yamaguchi did claw back to reduce the margin but the Indian managed to do just enough to seal the issue in her favour.
(REOPENS SPD 7)
Young shuttler Harsheel Dani notched up a stunning 21-15 21-10 win over seventh seed Lee Dong Keun of Malaysia in a men's singles match and will take China's Shi Yuqi next.
While sixth seeds Peng Soon Chan and Liu Ying Goh of Malaysia defeated Pranaav and Sikki 21-14 21-17, second seeds Praveen Jordan and Debby Susanto of Indonesia beat Arun and Aparna 21-13 21-17 in another match.
