Viktor Hovland was trying to keep up with Scottie Scheffler until he flipped the script on the final hole on Saturday with a 6-foot birdie for a 6-under 64.
It gave him a one-shot lead going into the final round of the PGA Tour's Travelers Championship.
From 25 feet and on the fringe, Scheffler ran his putt some 8 feet past the cup and missed it coming back for a bogey and a 67. It was the first time he trailed all day.
It was the second successive year Scheffler fell from the top of the leaderboard going into the weekend at the TPC River Highlands, though this was no cause for alarm. A year ago, he opened with a triple bogey, shot 72 and fell nine shots behind.
This was one hole, and he was only one shot behind as the world's No.1 player tries to win for the first time since the start to his season in the California desert.
Hovland was at 20-under 190 and gets another afternoon with Scheffler on Sunday (Monday AEST). The next closest players were Patrick Cantlay (64) and Akshay Bhatia (67), who were five shots behind.
"This is a golf course where you can see some numbers be shot. You know, guys can shoot pretty low," Scheffler said.
"Going into tomorrow just try to execute, have a good round, and see where that puts me."
Jason Day is the best-placed Australia and is in a tie for 50th, 15 shots behind Hovland.
Adam Scott is one shot behind day at four under par. Min Woo Lee is at even par and in 66th place.
Scheffler is enormously popular and the TPC Highlands had a vocal gallery. Hovland had plenty of support from a Norway contingent that drove over from Boston following a World Cup loss to France.
Hovland gave them plenty of opportunity to do the "row" that has become so popular in the stadium and subway stations and wherever they gather.
Hovland knows it well. Oddly enough, it was the first time he had seen it live.
"I mean, we're Vikings, so it's kind of in our DNA," Hovland said.
"It's kind of funny, that's the first time I've ever seen it. I think that's the first time we've ever done it, especially in the World Cup. So yeah, it took us 1,000 years to figure it out. I think it's pretty cool."