PGA Tour rookie Trevor Cone carded a bogey-free 9-under 63 for a 17-under, 199 total to take the 54-hole lead by one shot at the Barbasol Championship.
His previous low round was 65 and his previous best 54-hole score was 204, both at the AT&T Byron Nelson earlier this year where he finished T23, his best result so far.
"I hit it really well, hit it pretty close early on and then made a couple 10- to 15-footers on 2, 3 and 4., just got a rolling.
"Just played smart, fairways, greens, not get too aggressive. I mean, just hoped the putter came alive and today it did, hopefully it continues tomorrow. Just don't get ahead of yourself. Out here I think playing the par 5s is the most important thing. If you can take advantage of those, makes the rest of the golf course a little bit easier.
"Yesterday I played really, really solid. Didn't quite finish the round the way I wanted to, but good things finally started happening and snowballing. So I think the best thing today was something with the putter clicked. Made a slight tweak in setup and that seemed to get my eyes in the right place and see the lines a little better."
The American leads the field in Strokes Gained: Off the Tee (4.581), Strokes Gained: Tee to Green (11.710) and Strokes Gained: Approach the Green (8.361).
First- and second-round leader Lucas Glover of the United States posted a 69, his 11th straight round in the 60s, and moved down into a share of second place at 16-under.
"[This round was] sloppy, to be honest. Sloppy early and a little sloppy through the rain for a couple reasons, then a nice finish.
"Definitely need to clean a couple things up this afternoon and get ready for tomorrow. It's going to be a shootout and I can't hit it how I hit it today and expect to be there in the end tomorrow, so got to go work a little bit.
"I knew there were opportunities late. No. 15's always reachable no matter what the wind is and took advantage there. Then I hit a couple nice shots on 17. With that pin you've got the backstop, I knew that was a chance. So I knew I had some chances coming in, I just had to execute and finally did it."
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Another PGA Tour rookie, Vincent Norrman of Sweden, recorded his eighth straight under-par round on Tour with a 67 to move into second place. He has had two top-10 finishes so far this season (T9/Zurich Classic of New Orleans with teammate Matthias Schwab, T8/AT&T Byron Nelson).
France's Adrien Saddier lies in solo fourth place at 15-under after closing with a 67.
England's Nathan Kimsey's own 67 places him in a share of fifth place at 14-under alongside South African Jayden Schaper who carded a bogey-free 68.
Preferred lies were in effect during the third round.
