Adam Scott was swinging late for most of Saturday until the final move, uphill, when he holed a stunning eagle on the final hole to take the lead
After shooting a 63 on Friday, Scott's scorecard barely budged on Saturday as Poland's Adrian Meronk made a blistering birdie to equal the course record.
But two birdies on the back nine started a move that ended with an eagle that met with thunderous applause on the 18th hole just before 7 p.m.
Scott shot a 3-67 to move to 11-under, one ahead of Meronk after an extra-long day. of the third rounds caused frustration for some.
The rounds, which stretch into the early evening, are a gender split that Open officials will have to work out until next year as a mass of players battle it out for three.
There was frustration among some players as 161 - 78 women, 71 men, and 12 all-ability golfers - crammed into Victoria on Saturday,
"I know my game too. I'll just focus on that. And that's all I can do. And I hope that's enough for you at the end of the day."
Overnight leader David Micheluzzi battled to a two-over 72, while Min Woo Lee, brother of world No. 4 Minjee, dug out of a bunker for an eagle on the 18th hole.