ST ANDREWS, Scotland, Oct 4, 2012 (AFP) - Grace, a three-time winner already this year, bettered the course record on St Andrews' Kingsbarns course by two strokes with a 12-under par 60 for what he termed his best round ever.
"It could have been a 59 as I said to Zach (Rasego - caddy) when I hit it stiff on 18 that it could be close to a 59," said Grace.
"I had some opportunities, but you know, I never really made anything long.
"They were 12 to 15 footers in, which was nice, and it's nice just to have a bogey free round on a links course.
"You can say Kingsbarns is the easier one out of the three courses, but it's nice to get in these conditions and you can take advantage of it.
"But that round has to be my best ever. I won last year back home and the final round, the conditions were tough and it was playing long and I think it was good prep for this week."
The previous course record of a nine-under par 62 was set by England's Lee Westwood on route to victory in 2003.
Grace's score was three strokes fewer than his previous best Tour round of 63 recorded in last year's Joburg Open and matched this season in the Africa Open.
Grace's round of 60 was the lowest on Tour since England's Kenneth Ferrie shot a course record similar score in last year's Open de Andalucia.
While Grace was working his magic at Kingsbarns, Frenchman Victor Dubuisson produced a new course record of a nine-under par 62 on the famed Old Course despite dropping a shot at his 16th hole.
Dubuisson's round was one stroke fewer than the previous low of 63 set by three players including Northern Ireland's Rory McIlroy during the 2010 British Open.
Leading scores after round one:
60 - Branden GRACE
62 - Victor DUBUISSON
63 - Thorbjørn OLESEN
64 - Alexander NOREN, Fredrik ANDERSSON HED, Ashley HALL