Marc Leishman has been unable to back up his sizzling opening round at the Houston Open, dropping from the lead to 14th with the second round unable to be completed due to darkness.
American Martin Trainer, ranked No. 1,310 in the world, was the surprise leader at 10 under par, holding a one-stroke lead.
Leishman carded a five-under-par 65 in the first round to be tied atop the leaderboard with Americans Russell Henley, Talor (Talor) Gooch and Luke List.
He opened round two on the 10th hole and had bogeys at the par-4 12th and par-3 15th, before rallying at the par-4 first where he nailed a 246-yard approach to six feet for birdie.
The Victorian world No.35 managed only two further holes to sit at four under before play at Memorial Park Golf Course was suspended for the day.
With Thursday’s opening round delayed by rain, the field had to complete that round Friday morning before beginning round two.
Sixty-five players will finish their rounds Saturday morning before the cut line is determined although it’s virtually certain four-time major champion Brooks Koepka, at three over, will miss for the second straight week.
Trainer signed for a five-under 65 for his first round, then posted the same score for round two, with five birdies.
He leads Kevin Tway, whose second round 64 included eagles at the third and 13th, while another American Jason Kokrak was a further stroke back after six birdies through 11 holes completed.
Trainer won the Puerto Rico Open in 2019 as a rookie but made only nine cuts in 70 starts on the PGA Tour since then.
The 30-year-old opened this season with five missed cuts in a row.
“It is demoralising when you keep missing cuts over and over again,” Trainer said.
“On Tour obviously it’s tough to even compete and make a cut, let alone, you know, get to the top of the leaderboard.
“It’s been tough at times for me the last couple years not playing well, but now that I figured out a little bit of ball-striking, dropped some putts, it really can turn around that quickly.
“So I’m just grateful that that’s happening to me this week and hopefully I’ll keep it going.”
Adam Scott headed into the second round with a share of 12th but dropped two shots in his 13 holes to sit at even par along with countryman Cameron Smith, who carded a 69.
Jason Day had a disappointing 74 after an opening round 67 while Cam Davis had a second round 73 and at three over is set to miss the cut.