"I'm playing some good golf, hopefully I can go out tomorrow and play well". Afterall, his 63 in the final round of the 1973 U.S. Open at Oakmont stood as the gold standard of major golf scores for what feels like forever.
The South African, ranked 35th in the world, produced the record-breaking score after 31 rounds of 63 had been posted across the four majors, with Henrik Stenson and Phil Mickelson both having done so at last year's Open. Playing partner Paul Casey, who shot a three-under 67 to sit at level par, said: "I know when Rory (McIlroy) gets hot, Rory is awesome".
We'll let Michael Scott take it from here.
Grace made himself do it the hard way as his approach shot rolled off the back of the green - only for him to lag the ball up pin high and delight the Merseyside crowd by knocking in his 62nd and final stroke of the day.
On whether he could have matched the 62 on Branden Grace: "I think we could have been sniffing around those numbers as well".
On the Par-4 17th hole, he hit a lovely second shot on to the green that left him a tap-in birdie to go to 8-under. My caddie said "congrats, it's in the history books" and I had no idea!More news: 2 banks burnt as Policeman kills truck driver
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It is not the lowest score to par in a men's major though, with seven players scoring nine under on par-72 courses.
"My main thing was not wanting to finish with a bogey". I didn't really make any long putts but I just hit it really good today.
Grace drained a 15-footer at the first, an 18-footer at the ninth and had a tap-in birdie at the par-5 17th. Robert Streb shot 63 during the second round at last year's PGA Championship.
South Korea's Hyo-Joo Kim holds the record for the lowest round in any major with 61 at the women's Evian Championship in 2014. But he tugged his 2-iron to the left, and his chip was not great, leaving a 10-footer.
Last month, Justin Thomas shot 63 during the third round of the U.S. Open at Erin Hills, just the fifth to do so in that championship.
Grace said knowing now that he made history "makes it even more special than what it was".