Saina took just 21 minutes to beat Rachael while Kidambi Srikanth entered the third round with a 21-15 21-10 win over compatriot Ajay Jayaram in 25 minutes.
Saina has drawn the in-form Danish player Mia Blichfeldt, who beat Sindhu in the first round of the first Thailand Open in January. Srikanth starts his tournament against Indonesian Tommy Sugiarto.