"It's quite clearly the best round I've ever had," the 24-year-old, who is yet to win a European Tour title, said.
"My lowest round ever and to do it at the home of golf makes it even more special. I'm looking forward to tomorrow.
"I've never actually got to double digits before. Just kept the momentum going with holing some good birdie putts."
Hatton took full advantage of benign conditions on the Old Course, going out in 30, to move in front of overnight leader Ross Fisher who carded a 69 at Carnoustie.
Fisher is three strokes back on 14-under with Sweden's Joakim Lagergren and South Africa's Richard Sterne a further stroke behind.
(Reporting by Martyn Herman, editing by Pritha Sarkar)
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