Scotland's Robert MacIntyre will take a five-shot lead over Scottie Scheffler into the weekend at the BMW Championship after firing a bogey-free 64 on Friday in Owings Mills, Maryland.
MacIntyre's 6-under-par round followed a sterling 62 at Caves Valley Golf Club to open the second leg of the FedEx Cup playoffs.
Now at 14-under 126, MacIntyre is halfway home to his third PGA Tour victory after capturing the Canadian and Scottish Opens last year.
He said he doesn't recall having a lead through 36 holes as large as this one.
"Not as a professional, I don't think. But I've had it before as an amateur," MacIntyre said.
"Yeah, again, it's only 36 holes gone. There's a long way to go. I'm comfortable with who I am. I'm comfortable with the team around me, and I'm comfortable on this golf course. Just go and play golf."
Scheffler made five birdies and no bogeys in his round of 65, capped with a difficult two-putt par from 73 feet on the last hole.
Sweden's Ludvig Aberg (8 under) and Japan's Hideki Matsuyama (7 under) are third and fourth, respectively, after they each shot 64 Friday.
Maverick McNealy joined the 64 brigade and moved to 6 under for the tournament, tied with Michael Kim (66) and Englishman Tommy Fleetwood (69) for fifth.
Northern Ireland's Rory McIlroy improved by four shots from Round 1 to 2, his 66 lifting him to 4 under par.
They're all looking way, way up at MacIntyre, who turned in a card with three birdies on each nine.
While his Thursday round was marked by a multitude of long putts, he only had two of those on Friday: a 17 1/2-foot birdie at No 4 and a sweeping 29-footer at No 14.
Instead, MacIntyre relied on his approaches to take him a long way. He led the field in strokes gained: approach the green and hit 15 of 18 greens in regulation.
"It's just about picking smart shots, smart targets and then just dealing with what comes," MacIntyre said.
Only the top 30 players in the FedEx Cup standings at the end of this tournament will advance to next week's Tour Championship.
Once they're there, everyone will start at even par, as the tour eliminated the controversial "starting strokes" format.
Kim entered the week 42nd in points and is projected to jump to No 26 in his current position. England's Harry Hall, currently 45th, is projected to snag the 30th and final spot; he's tied for eighth at 5 under after a 67 Friday.
"I like to look at the numbers," Hall said, "and I know if I can just average gaining 1.2 strokes a round, then it equates to playing really good golf and getting really far in the FedEx Cup."