But Sindhu moved ahead with a couple of powerpacked returns which Sun failed to negotiate. The Chinese also faltered with a lift and also hit wide as Sindhu reached 10-6.
A few errors helped Sun make it 8-10 before Sindhu entered the interval with a 11-8 advantage.
Sindhu continued to extend her lead even as Sun tried to vary the pace of the rallies but her errors continued to pile up as the Indian was soon 19-11 up. Sindhu then grabbed the match point when Sun let go of the shuttle as it kissed the back line and then the Indian pushed the shuttle at the back, leaving the Chinese stranded before letting out a joyous scream.
Saina Nehwal had clinched the China Open in 2014 before finishing runners-up last year.
Sindhu had reached her maiden Super Series final at the Denmark Open last year but the title eluded her then as she lost in straight games to 2012 Olympic champion China’s Li Xuerei.