AVONDALE, La. — Scott Stallings and Trey Mullinax shot a best-ball 11-under 61 to top the Zurich Classic leaderboard after a weather delay longer than seven hours prevented half of the 80 teams from even teeing off Thursday.

Stallings and Mullinax, who started on the back nine, birdied their last four holes at the TPC Louisiana — and seven of nine holes after the turn — for a one-stroke lead over two teams.

“We both played solid all day — missed a couple putts, short ones, but made a couple longs ones,” Mullinax said. “We both putted really well. Scott was really good with his wedges.”

Martin Laird and Nick Taylor, who were in the same group as the leaders, finished at 10 under. But the team of Brian Gay and Rory Sabbatini had both of the top teams in their sights after birdies on the first five holes of the back nine got them to 10 under through 14 holes.

All but 13 teams still had part or all of the first round still to play when darkness stopped play. Seventeen teams were within five shots of the lead.

The Zurich Classic is the only team even on the PGA Tour, and the format alternates between best ball in the first and third rounds and alternate shot in the second and final rounds.

The Australian tandem of Jason Day and Adam Scott, who started on No. 10 at 7:39 a.m. could be seen jogging down the fairway on No. 8 in hopes of completing their round on the ninth hole as the sun set just past 7:30 p.m. local time. But as Scott lined up for his second shot on a fairway bunker, the horn sounded to signal that would be the last hole, and that players who hadn’t finished the first round would have to be back on the course at 7 a.m. on Friday.

Scott backed away from his ball in a fairway bunker and briefly assumed a defeated, slouched posture, knowing he’d be among players with an early wake-up call the next day.