PGA Tour rookie John Pak fired a seven-under 63 to hold an early lead at the Charles Schwab Challenge on Thursday, with Scottie Scheffler five back in his first round since his major triumph.

Pak and Scheffler started their rounds identically – with an eagle on their first holes – but that was as close as the PGA Championship winner got to the young American after that.

Pak holds a three-shot lead over the field after his career-best round, adding five birdies to that opening two on the 10th, which he holed out from 147 yards.

Nine golfers are tied for second place as four-under, including J.J. Spaun and England’s Matt Wallace.

Tommy Fleetwood and Brian Harman are among a group four back, and Scheffler headlines the 15 players who are five strokes behind.

Jordan Spieth, Scheffler’s fellow hometown favourite, shot 69 with birdies on two of his final four holes.

After his opening eagle three on the first, Dallas resident Scheffler birdied the second but then played the final 16 holes in one over.

He will have to come from behind again to prevail at Fort Worth, just as he did at Quail Hollow – where he faced the same first-round deficit before surging into the lead in the third round and repelling a Sunday charge from Jon Rahm.

“On a day where I didn’t hit a lot of fairways on a golf course where you have to hit a lot of fairways, I posted a decent score,” Scheffler said.

“Anything under par around here in these conditions isn’t a bad score. Obviously, I wish it was a little bit lower, but overall I feel decent about the position I’m in.”

Watch the second round of the PGA Tour’s Charles Schwab Championship on Friday at 9pm on Sky Sports Golf and 10pm on Sky Sports Main Event.