Rahm's 71 on Saturday included a double bogey and has left him 12 shots back of Penge, tied for 28th as the Ryder Cup winner tries to surpass Seve Ballesteros as the tournament's most successful golfer since the creation of the European Tour in 1972 with a fourth national title.
But Penge is on 16-under for the tournament after recording a seven-under 64 in round three.Â
The overnight leader started the day with a third-hole bogey but then went on a red-hot run, going under par on eight out of 10 holes to distance himself from the pack.
"Whatever the outcome is, it's going to be a great experience, great memories for me," Penge said.
"Tomorrow doesn't define anything, it's just another day, an 18-hole round of golf."
Playing partner Joel Girbach of Switzerland is his nearest challenger, four shots back. Daniel Brown and former Masters winner Patrick Reed are five back, followed by Tom McKibben, who is six behind.
The 27-year-old Penge even had to put together his spectacular round after breaking his wedge when he got stuck behind a tree on the second hole.
"I knew it was going to break," he said. "I kind of picked a club I didn't think I was going to need the rest of the way, just made sure not to hit my hand on the tree."
Penge had begun the day with a one-shot lead and will now bid for his third tour win, after also prevailing this year at the Danish Golf Championship and the Hainan Classic.
The leading Australian remained David Micheluzzi, whose 74 left him one over for the championships in joint-48th place, while Jason Scrivener's 75 put him on four over, tied for 71st.
