World number 76, Sharath started the final-four clash on an attacking note pocketing the first two games 11-5, 11-6 before Tianyi regained touch and reduced the difference by pipping the Indian 16-14 in a keenly contested third game.
However, Sharath held his nerves to quell the late charge and pocketed the next two games 12-10, 11-9 to round off the score and set up a summit clash with Li Ching of Hong Kong, who beat Egyptian Lashin El-Sayed 4-1 in the other semi-final.
Earlier, the lanky Indian survived several anxious moments before getting the better of Salifou Abdel-Kader of France 4-3 in a long-drawn quarterfinal.
All the other Indians have already crashed out of the tournament.
Earlier this month, Sharath had notched up the biggest title of his career when he clinched the US Open crown in Michigan.
Sharath in Cairo Open quarters
Indian paddlers off to mixed start in Egypt Open
Food fests, fun deals in Singapore, Hong Kong
Sharath wins US Open TT title
Bangkok's loss is Hong Kong's gain