Madappa, who was tied 13th after two rounds is now tied 22nd, while Rahil Gangjee, one of the only three Indians to have won a title on the main Japan Tour, shot 75 and was placed further back at tied 52nd spot.
Madappa was three-over in the first seven holes, before he had back-to-back birdies on eighth and ninth. However he gave one of them on 10th and parred the remaining eight on a tough day at the Sobu Country Club.
Gangjee had two birdies, four bogeys and a double.
Japan's Yosuke Asaji will take a one-shot lead into the final round after he posted a three-under-par 68. The 25-year-old Japanese is seeking his first professional win since turning pro in 2012. He is now four-under-par 209.
Zimbabwean Scott Vincent, meanwhile, returned with a 68 to give himself another chance for his maiden breakthrough on the Asian Tour.
Vincent, together with Korea's Y E Yang, and Japan's Jinichiro Kozuma are bunched in fourth place, three shots back of Asaji.
The winner of the Asia-Pacific Diamond Cup will qualify for the 148th Open which will be held at Royal Portrush, Northern Ireland in July.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)