Srikanth had earlier defeated world No 1 Son Wan Ho of South Korea to reach the summit clash.
Compatriot Srikanth, who was playing on another court, also reached the last four round with a 21-15 21-14 win over Chinese Taipei's Tzu Wei Wang. Son looked unsafe when he came close 10-12 from 6-11 but failed to take the advantage. The duo were locked 3-3 initially but Srikanth slowly moved away to make it 11-6 with a backhand tap at the net which Son couldn't negotiate.
But Son didn't flinch and kept rallying hard till the end to find crucial points. While Srikanth banged a smash at the net, Son erred in hitting long.
"But, once I chose to attack, work up a good pace which I haven't done a bit before that phase in the final, I knew that I would be back in the match", Srikanth said.
10 still in critical condition after London fire
He also cautioned there may have been people in the tower that police are not aware of, which would add to the death toll. London Fire Brigade said it had rescued 65 people and that firefighters managed to battle all the way to the top floor.
"I am very happy now". It is the last tournament before the World Championship.
Sakai, on the other hand hit a lovely drop at 27-26 to win the game. "I hope there is a lot more to come", he said.
"In the first game I could not gain control and my body still felt heavy, but I fixed it in the second and third game by moving as fast as I could to control the game", said Sakai.
The decider saw Sakai marching ahead with a 6-2 lead which he extended to 11-9 at the changeover. His net dribbles were better than Sakai and with Sakai struggling with precision, the Indian zoomed to a 19-11 lead and sealed it with two lucky net chord points.
"Well not my day I guess". "Even the one today was exhausting but this time I managed to be consistent during the important points, and it worked for me. Thank you everyone for the support this week", Prannoy said after the defeat.