SAN FRANCISCO (AFP) — Ben Griffin, warming up for his Ryder Cup debut, fired a two-under par 70 on Saturday to stay atop the leaderboard at the PGA Procore Championship, with amateur Jackson Koivun and top-ranked Scottie Scheffler in pursuit.

Griffin, who won twice this year and is a captain's pick for the US Ryder Cup team, led by three going into the round.

With a 54-hole total of 16-under 200 he was still one stroke ahead of world amateur No. 1 Koivun after firing three birdies in a two-under par 70 at the Silverado Resort in Napa, California.

But both will be wary of four-time major champion Scheffler, who put himself in position to strike for a sixth title of 2025 with an eight-under par 64 for a 14-under par total of 202 — one stroke in front of South African Garrick Higgo (66).

"Every player on this tour is a really good golfer and there's two very, very good ones that are right behind me," Griffin said.

"So I know I've got to keep the pedal down, stay aggressive. (I) need to probably make some more putts, but just got to keep hitting it the way I am."

Griffin rolled in birdie putts of 19 feet and 26 feet at the fourth and ninth. His lead was as large as five strokes as those chasing encountered trouble.

It was at two after he birdied the par-five 15th, the cushion cut in half when he bogeyed the par-five 18th.

Koivun started the day three off the lead but dropped back with bogeys at the third and fourth.

He rebounded with birdies at eight and 11, then drilled a 43-foot eagle putt at the 12th and rolled in a 20-foot birdie at 14.

He added another birdie at the 15th and a week after leading the United States to a Walker Cup win over Great Britain and Ireland will play in the last group of a PGA Tour event on Sunday.

Scheffler, who started the day eight off the pace after a frustrating first two days, found his groove.