PERTH, October 19, 2013 (AFP) - In blustery showers, Ninyette fired a five-under par 67 to lead the co-sanctioned European tour event at eight-under 208 ahead of Rumford among a three-way share of second place.
Ninyette, 26, and rated 1019 in the world, said he had relied on invaluable pointers from his caddy about how best to tackle the Perth course.
"He's been a member here for most of his junior golf career," Ninyette said.
"He reads the greens well and knows the course well."
Rumford shot a seven-under 65 on Saturday to be just one stroke adrift of Ninyette and if not for a three-putt on his final hole, he would have broken the course record set by Michael Hendry and Alejandro Canizares last year.
Rumford is eyeing his third European Tour title of the year after becoming the first Australian in 41 years last May to win back-to-back European Tour titles when he followed up his triumph in South Korea with victory at the China Open.
"Winning in front of your home crowd - there would be nothing better than that," Rumford said.
"Obviously it's massive just to have won back to back this year. You win a couple of times and you think, 'let's go out and do it again'.
"It doesn't quite happen that way and you realise how hard it is to win out here."
"But I've got myself in position to win. I'll be working hard and that's what I'll be focusing on for the next 24 hours."
Denmark's JB Hansen and South Korea's Jin Jeong joined Rumford at seven under.
Overnight leader Peter Hedblom, who needs to win the tournament in order to keep his European Tour card, fell four shots off the pace after a three-over 75.
American world number 21 Dustin Johnson dropped out of contention after falling 10 shots off the pace, but defending champion Bo Van Pelt was still in the running at four under.
Australians Rohan Blizard and David McKenzie both had a hole-in-one during the third round.
Leading scores after the third round of the Perth International at Lake Karrinyup (par-72) in Perth on Saturday (Australian unless stated):
208 - Brody Ninyette 72-69-67
209 - JB Hansen (DEN) 70-73-66, Brett Rumford 71-73-65, Jin Jeong (KOR) 68-72-69
210 - Jason Scrivener 75-67-68, Fredrik Andersson Hed (SWE) 69-73-68, Richard Finch (ENG) 72-69-69, James Nitties 68-73-69, Ross Fisher (ENG) 72-67-71
211 - Joel Sjoholm (SWE) 71-73-67, Danny Willett (ENG) 72-71-68, Michael Hoey (NIR) 73-69-69
212 - Bo Van Pelt (USA) 70-71-71, Dimitrios Papadatos 69-71-72, Soren Hansen (DEN) 71-69-72, Peter Hedblom (SWE) 68-69-75
213 - Oliver Fisher (ENG) 72-72-69, Nick Cullen 69-73-71, Marcus Fraser 72-70-71, Josh Younger 70-70-73