Troy Matteson kept up his furious pace with a five-under 66 to lead by three from three-time defending champion Steve Stricker going into the final round of the John Deere Classic.
Following rounds of 10 under and three under, Matteson was stellar again, carding seven birdies against a couple of bogies to sit 18-under overall.
Stricker, looking for his fourth straight John Deere title, matched him shot for shot - although he left it late.
Two under through 13, Stricker had four consecutive birdies from 14 before bogeying the 18th, where Matteson also dropped a shot.
Winning again would enable Stricker to fly to The Open next week having equalled the feat achieved by Young Tom Morris at Prestwick in 1968-72 and also by Walter Hagen at the USPGA Championship, Gene Sarazen in the Miami Open and Woods at both Bay Hill and the Buick Invitational.
And Matteson was under no illusions as to who will have popular support on the final day.
"You always want to be ahead rather than behind," he said. "Every stroke you can gain is good.
"Steve is a great guy. He's the kind of guy that personifies what we're looking for on the Tour. He's the kind of guy you can tell your kids to use as a role model.
"He's just a really good guy. He's a good guy to have at the top of the leaderboard at any tournament, especially John Deere because of what he's done here in the past.
"I think it'll be really fun to play with him.
"I'm pretty used to if I'm playing in the last couple of groups, I'm not the guy people root for, so I think that it'll be pretty normal for me."
Stricker said the key for his playing partner would be dealing with the pressure.
"I've been in this position Troy's in, and it's a difficult position because you have the expectations that you should go out and win," he said.
"It's still very hard, because guys behind you are going for broke and they can be a little bit more aggressive and take a shot at pins.
"That's what he's going to have to deal with tomorrow."
Stricker finished the day with 10 players within three shots of him, notably local favourite Zach Johnson, just one stroke back.
Like the two men ahead of him, Johnson carded seven birdies and two bogeys, leaving him alongside Brian Harman on 14-under.
Billy Hurley III, who had a best-of-the-day seven-under 64, 2006 champion John Senden and JJ Henry were 13-under, while England's Gary Christian was in a group of five players on 12-under.