MIAMI (AFP) — Austin Eckroat was clinging to a one-shot lead when darkness halted play on Sunday at the US PGA Tour's Cognizant Classic, which was headed for a Monday finish after thunderstorms stopped play for three and a half hours.

Overnight co-leader Eckroat had back-to-back birdies at the fourth and fifth and was 15-under for the tournament through seven holes when darkness fell.

He and overnight co-leaders Shane Lowry of Ireland and David Skinns of England didn't tee off until after the lengthy thunderstorm delay.

Eckroat called it "just a weird day."

"Mother Nature, there's nothing you can do about it," Eckroat said.

"I almost didn't think we were going to play at all today, so I kind of shut off for a little bit and then I had to get back into competitive mode."

Lowry, the 2019 Open Champion, slipped down the leaderboard with a bogey at the fifth shortly before darkness halted play.

Skinns, chasing a first title at 42, had bogeys at the first and third.

South African Erik van Rooyen made a big charge before the storms struck, opening with birdies at his first six holes on the way to an eight-under par 63 that put him in the clubhouse on 14-under 270.

American Jake Knapp was 13-under with three to play and Keith Mitchell was in the clubhouse at 12-under after a final-round 65.

Van Rooyen was delighted to turn things around on Sunday after a third round that left him feeling "slightly crabby" over the shots he thought he left on the course.