In a tournament that gives the winner a start at the famous Augusta Masters the following year, Fernandes, who began the day at tied 16th, is now one-over 217 and tied 10th.
Udayan Mane, who was fifth overnight crashed to one his worst rounds of the year as he ballooned to 13-over 85 and dropped to tied 39th at 10-over 226.
Aman Raj (74) was 11-over 227 and tied 46th, while Viraj Madappa also had a rough day with a card of 83 and dropped to 15-over 287.
He is 12-under and his closest pursuers are at 4-under and needing to go exceptionally low on the Composite Course to have a chance of overtaking him.
The relentless Chinese Taipei player Pan Cheng-tsung (73-68-71) is among the group at 4-under-par who will be chasing Murdaca tomorrow, along with China's 16-year-old Jin Cheng (71-69-72) and another Australian, Todd Sinnott (67-71-74).
Fernandes, who was born in Karnataka and grew up in Dubai and then has lived in US for last years and where he also attended the IMG Golf Academy in Brandenton, Florida.