American Sam Burns produced a stretch of five birdies in six holes Friday, and he is tied with Keegan Bradley for the lead at the midpoint of the Valspar Championship in Palm Harbor, Florida.
Burns produced the best score of the week so far, an eight-under-par 63, to sit at 12-under 130 through two rounds.
Compatriot Bradley, the first-round leader, was five under on Friday, leaving him at 12 under as well.
They both set the event's 36-hole scoring record, topping the mark of 131 set in 2002 by South Korea's KJ Choi.
The pair have a four-shot cushion over the next contenders, Lucas Glover (six under on Friday), Charley Hoffman (five under) and Max Homa (three under), all at eight under overall.
South Africa's Charl Schwartzel (six under), England's Tom Lewis (six under), South Korea's Sungjae Im (four under), Zach Johnson (four under) and Hank Lebioda (two under) share sixth place at seven under.
Ireland's Graeme McDowell missed the cut after adding a 73 to yesterday’s 74.
Burns has at least a share of the lead in a PGA Tour event for the fourth time this season, the top mark on the circuit, after tying the lowest round of his career at 63. He also had a 63 in the final round of the 2020 American Express event.
The 24-year-old former LSU All-American is still seeking his first PGA Tour victory. His best result was third place at the Genesis Invitational near Los Angeles in February.
Burns played a bogey-free round Friday, carding three birdies on the front nine before his hot streak to open the back nine.
Looking ahead to trying to maintain his form for two more rounds, Burns said: "I think for me it's just sticking to what I've been doing, having a good game plan going into the day.
"And then there's going to be times in the rounds where it gets tough, and I think in those moments just hanging in there mentally and just being ready for when it turns.
"So I know over the weekend there will be some challenges, and I'm excited for the opportunity."
Bradley, who started play Friday on the back nine, had four birdies and a bogey on the day before closing with an eagle on the par-4 ninth hole.
His 115-yard chip shot landed a few feet above the pin, the spun back into the cup.
"I turned a good day into a great day," Bradley said. "Man, it was a fun day, and what a way to finish. It was a blast."
England's Paul Casey, the event's two-time defending champion, shot even par on Friday and dropped to a tie for 33rd at three under.