Louis Oosthuizen will have to hold off a strong chasing pack on Sunday afternoon if he is to win a first European Tour title in two years at the ISPS HANDA Perth International.
The South African had seen his three-shot overnight lead cut to one early in the fourth round but birdies on the seventh and eighth got him to 16 under and restored some breathing space heading into the final nine holes at Lake Karrinyup Country Club.
American Peter Uihlein had two birdies on the front nine to emerge as Oosthuizen's closest challenger at 14 under, with Grégory Bourdy, Alexander Levy and Jason Scrivener a further shot back.
A win for Oosthuizen would he his eighth on The European Tour and continue a remarkable start to the season for South Africans, who have so far won five of the ten events.
Home favourite Scrivener picked up a birdie on the first after an impressive pitch left him a short putt and that soon had him within two of the lead as Oosthuizen left his second shot short at the second.
When Scrivener took advantage of the par five third, the lead was down to a single shot and Uihlein soon joined the Australian at 13 under courtesy of a birdie on the fourth.
Scrivener then got up-and-down from a bunker on the seventh to take a share of the lead but Oosthuizen repeated the trick from the same hazard just minutes later to get his nose back in front.
That birdie seemed to spur the 33 year old on and he put his tee-shot on the par three next to seven feet and rolled in the putt to get to 16 under.
That was enough for a three-shot lead when Scrivener left his par putt on the ninth short but Uihlein, after brushing the hole on a few occasions, got one to drop for a birdie.
Bourdy had six birdies through 14 holes to make his surge up the leaderboard while fellow Frenchman Levy also had six birdies to go with a double-bogey on the sixth.
Romain Wattel was then at 12 under, with Peter Senior and Mardan Mamat a further shot back.