Potomac - Justin Thomas, who joined two of golf's most exclusive clubs this year by shooting 59 in a PGA event and 63 in a major, insists more low rounds are coming.
The 24-year-old American fired a nine-under par 63 in the third round of the US Open two weeks ago at Erin Hills, becoming only the 29th player to match the low 18-hole score ever posted in any major and just the fifth to shoot 63 at a US Open.
But 12th-ranked Thomas, a favorite in the PGA National that starts on Thursday, says he has another such round in him.
"When I get going, I can go low pretty well," Thomas said on Wednesday. "I mean, this sounds probably pretty arrogant, but I feel like I'll shoot another 63 in a major at some point in my career.
"I don't know if it will ever happen, but I feel like I have the game to do so."
Only two players have fired major rounds of 63 twice and both of them are multiple major winners.
Australia's Greg Norman did it in the second round of the 1986 British Open at Turnberry on his way to victory and in the first round of the 1996 Masters, when a shocking final-round collapse left him second to Nick Faldo.
Fiji's Vijay Singh did it at the second round of the 1993 PGA Championship at Inverness and the 2003 US Open at Olympia Fields, but didn't win either time.
Sweden's Henrik Stenson shot 63 in last year's British Open final round to win at Royal Troon, a feat Thomas saw as much superior to his effort, the lowest sub-par round in US Open history.
"To do it on Sunday when someone's chasing you down is way more impressive than my 63," Thomas said.
Last January, Thomas became only the seventh player in PGA history to shoot a 59, a closing eagle in the first round of the Sony Open in Hawaii making him the youngest of the sub-60 set, even though it came five months after Jim Furyk has set the new mark to beat with a 58 in the final round of the Travelers Championship.
Thomas said there was no way to tell that greatness was coming when working on the practice range before a round.
"You don't feel a round like that coming, but you definitely feel more confident going into the day than you maybe do other days when you're not hitting it as well or warming up as well, if that makes sense," Thomas said.
"There have been days when I've had great rounds when I haven't slept well or when I kind of just wake up crabby or not in a good mood. It doesn't happen that often, but crazy things happen in this game."
In the final Sunday pair at a major for the first time, Thomas made bogeys on three of the first five holes and never recovered as Brooks Koepka won his first major title. Thomas finished ninth.
"I didn't know how I would feel, how I would react," Thomas said. "I didn't have it that day. I really fought as hard as I could to shoot 75.
"I learned a lot about myself. I handled it well. I was comfortable. I hung in there."
Asked which of his historic rounds was more difficult, Thomas opted for the 63.
"The 63 was probably harder," Thomas said. "They're both obviously my two best rounds of golf. But 59 was 11-under, the 63 was 9-under and I guess in terms of history, I would think there's less 63s than 59s?
"I know nothing about history obviously. I just know I like being a part of it. They were both great days, memorable days and definitely days I won't forget."