The American carded a closing 64 as he won the 2020 US PGA Championship and he equalled that mark to move to nine under heading into the weekend at Royal St George's Golf Club.
He only finished in a tie for 71st in the Rolex Series event at The Renaissance Club but revealed that the links experience had held him in good stead in his debut at the game's oldest Major.
“Last week I wanted to win but I came out of it learning a lot more,” he said. “The style of golf is different and last week helped tremendously.
"I wouldn't be here through these two rounds if I hadn't played last week at the Scottish.
Last week I wanted to win but I came out of it learning a lot more. The style of golf is different and last week helped tremendously
"I've played in firm conditions. I can think of places I've played in tighter, drier conditions but just having fescue fairways and the ball sitting a little different was huge to see last week.
"I changed my irons, my nine through seven iron that I normally have blades in, I changed to the MCs (muscle cavity) strictly because I couldn't find the centre of the face."
The 24-year-old is renowned for his iron play and he turned in 31 courtesy of a long putt on the eighth and approaches inside six feet on the first, fifth and ninth.
He added a 12 footer at the 11th to two more remarkable irons into the 12th and 14th and was four ahead and on track for a course record.
A dropped shot on the next stalled his momentum but he still had a six footer at the 18th for a 63.
"I had no clue what any course record was," said the man third in the Race to Dubai Rankings in Partnership with Rolex. "I don't know any of those numbers. I'm awful with that stuff knowing ahead. Now I do know.
"But I was just trying to make a lot of birdies. The bogey on 15 today was a little unfortunate. I hit a good second shot out of the rough, put myself in a good position, just didn't have enough speed.
"But you know, it's going to happen. Guys are going to make birdies, you're going to make bogeys, and I'm very pleased with today. I just need to continue that into the next couple."