World number three Saina came out and pulled off a great performance, saving two match points to defeat reigning World Champion Carolina Marin of Spain to retain the crown she won last year.
The top seeded won the one-hour and 19-minute marathon final 19-21, 25-23, 21-16 and clinch the Grand Prix Gold crown.
The result means that Saina has completed a hat-trick of wins against the second seeded Carolina in as many meetings between them.
Kashyap beat compatriot and World No.5 Kidambi Srikanth 23-21, 23-21 in 52 minutes.
In mixed doubles, Indian pair of Manu Attri and K Maneesha went down to top seeded Indonesian combo of Riky Widianto and Puspita Richi Dili 17-21, 17-21 to finish runners-up.