From a comfortable position of 96/1, KKR dragged themselves into a difficult situation in the end. They will play CSK in the final on Friday.
Dhoni smashed three boundaries in the final over to take CSK home.
Yediyurappa, who is in his home town Shikaripura in Shivamogga district, watched the thriller on LCD screen sitting in his car.
The wicketkeeper-batter smashed a last-ball six to help his side beat Delhi Capitals.
Both Delhi and Bangalore are unchanged from their previous matches.
Ripal scored 18 off 20 balls on his IPL debut as Delhi Capitals defeated CSK by three wickets in a low-scoring game.
Chasing 137, Delhi hunted down the target with two balls to spare and now sit on top of the points table.
Having already sealed a playoff berth, Rishabh Pant-led Delhi Capitals made one change to their XI, by bringing in Prthvi Shaw.
Steve Smith and Rishabh Pant top-scored with 39.
The stumper, who was wearing a helmet, was lucky to miss Pant's wild swing.