No player since Padraig Harrington in 2008 has successfully defended the Open Championship. Jordan Spieth is in the perfect position to break that streak at Carnoustie.
The American carded a bogey-free six-under 65 to vault to the top of the leaderboard with one round to play. He is joined there on nine-under by Xander Schauffele and Kevin Kisner, with Kevin Chappell two shots further back in fourth.
Francesco Molinari is alone on six-under, with Tiger Woods, Rory McIlroy, Matt Kuchar, Alex Noren and Webb Simpson amongst those bunched together on five-under.
Spieth set the tone by driving the first green - the only player to do so on Saturday - and converted the eagle putt. He picked up three more shots at the fourth, 11th and 14th before draining a superb birdie putt at the punishing 16th.
It all added up to a sixth bogey-free major round for the 23-year-old American since 2015 - the most of any player in that span.
Consequently, he's in pole position to claim a second successive Open victory and his fourth major championship in all.
It would also be his first victory anywhere in the world since Royal Birkdale last year.
"I felt like I had something I had to prove to other people with last year's Open and to myself," he said. "Really to myself more than anything. I don't feel like I have to prove anything to anyone at this point. I'm playing golf for me now. I've kind of got a cleared mind. I've made a lot of progress over the year that's been kind of an off year, a building year.
"I've got an opportunity to make it a very memorable one tomorrow. I feel like my game's in good shape. It's progressed nicely. We've got pretty much a new tournament tomorrow.
"I feel like I'm rolling."
Meanwhile, Rory McIlroy was bullish on his prospects of winning his first major since the 2014 Open at Royal Liverpool, despite bogeying two of his final three holes to fall back to five-under for the championship.
"I just need to get off to a fast start," said the Northern Irishman. "I'm obviously disappointed after the way I finished but I'm still in the tournament. I'm only a few shots behind.