American Scheffler, who entered the event as the new world No. 1 after three successive wins, holds a three-under 10-under lead in the first major of the season.
But he’s being chased at Augusta National by Aussie Smith, who has won twice this year and, perhaps more importantly, loves it here.
He’s made the cut in his previous five appearances, including two top 10 finishes and a second-place finish in 2020.
That year, the Queenslander secured a place in event history by becoming the first player to shoot in the 60s in all four innings.
In the second-to-last homer on that occasion, he was the only player to sign for a score in the 60s on a day when the scoring average was the fourth-highest since the 1980s.
World number 2 Jon Rahm worked for a 77 while Tiger Woods signed for a 78 – his worst score in more than 90 rounds in this tournament.
Scheffler, who held a five-stroke lead at the halfway mark, had four strokes ahead as he played the last before having to take a penalty after his drive hit a tree on the left of the fairway.
But the 25-year-old is still in charge as he offers to join Ian Woosnam (1991), Fred Couples (1992), Tiger Woods (2001 and 2002) and Dustin Johnson (2020) in claiming a green jacket as highest ranked player in the game.
Scheffler, who has recorded top-20 finishes in his two previous starts here, led by six at one point after reaching 11 under before opening the door slightly with his closing bogey.
“I felt pretty comfortable,” said Scheffler, who has Teddy Scott, who helped Bubba Watson win twice in this event, on his bag. “I had a lot of fun there. When I’m in the lead, I try to stay ahead and not think too much – just go play golf.
On what happened on the last hole he added: “You hate to bogey the last hole but the way I bogey felt like a par so definitely a good end to the day and I can’t wait See you tomorrow.”
Smith, who started the day six shots off the lead, birdied at second, sixth, eighth, 10th, 13th and 15th as the 28-year-old stormed here again.
“It was really tough today,” he said. “I think I did a good job staying to myself, staying patient with the course.”
When asked what he thought it would take to win on this occasion, Smith added: “Shoot the lowest score again tomorrow.”
With 26 of the last 31 winners of this event having made it into the final group on Sunday, the record books indicate either Scheffler or Smith will emerge victorious.
Danny Willett in 2016 was the last player to triumph outside of the final couple and Korea Sungjae Im leads the group aiming to achieve that feat on this occasion.
The 2020 runner-up is five behind Scheffler in third place after a 71, with 2011 winner Charl Schwartzel and 2019 Open champion Shane Lowry two strokes further in fourth after tying 73.
Schwartzel hit his second shot for an eagle in the tenth to go six under before dropping four shots over the final eight holes.
Johnson sits just inside the top 10 alongside Open champion Rory McIlroy, Collin Morikawa and Tommy Fleetwood.
Defending champion Hideki Matsuyama slipped 11 shots down after a 77, with Woods falling 16 back after his worst effort on this course.
Bob MacIntyre heads into the final round sitting tied for 36th out of six – one ahead of Woods – after failing to birdie in a 76, which was also his worst effort here, albeit in just seven homers.