The 23-year-old Australian, making his debut on the Saudi-funded tour, shot a seven-under-par 65 under lights on Saturday to enjoy the lead with Peter Uihlein (66) after three rounds at Riyadh Golf Club. Uihlein is also chasing his maiden LIV title.
The pair sit at 16 under and one stroke clear of another American Talor Gooch, who carded his third 67 of the week in the season-opening event.
It's the first time a LIV tournament has been played over four rounds, not three, since the tour launched in 2022.
Smylie's bogey-free round included five birdies and an eagle on the 627-yard par-3 fifth, thanks to a monster approach shot to the green.
The Queenslander, son of former tennis players Liz and Peter Smylie, has had only had two bogeys across three rounds and will be chasing a third professional win on Sunday.
He turned pro in 2021 and won the WA Open and Australian PGA Championship in late 2024.
A trio including former world No.1 and two-time major winner Jon Rahm (67) of Spain are within striking distance just two shots behind.
Marc Lieshman (68) sits at 10 under, Lucas Herbert (65) nine under and Cameron Smith (68), the 2022 British Open champion, at eight under.
The Aussie quartet have stormed back into team event contention, combining for 43 under to leave Ripper GC third and just two shots adrift of leaders Torque GC.
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