Chris DiMarco moved into a one-shot lead over a surging James Driscoll at the $5.5 million (4.3 million pounds) Zurich Classic of New Orleans when third-round play was suspended due to darkness on Saturday.
India's Arjun Atwal began the day with a stroke advantage over the field but slipped down to third after a double-bogey on the par-five seventh left him on one-over through 10 and two adrift of the leader at 10-under.
After two tournaments without disruptions, the foul weather that has blighted the PGA Tour this season returned, with heavy rain and severe thunderstorms at the TPC at Louisiana delaying the start of play five hours.
Weather permitting, the third round will resume on Sunday morning with the final 18 holes following in the afternoon.
Back in action for the first time since his playoff loss to Tiger Woods at the U.S. Masters three weeks ago, DiMarco was flawless once play began, going four-under through 10 holes to leave the American at 12-under for the tournament.
Driscoll, however, was having the round of the day when the players were called in, going six-under-par through 11 holes to vault up the leaderboard.
"I'm very happy that we got 10 holes in today," DiMarco said.
"That saves my legs a lot. Tomorrow is going to be a long day but the one good thing about it is I don't have to sit around all morning and wait to tee off."
Americans Lucas Glover, J.J. Henry and Tim Petrovic sit one shot further back on nine-under with holes to play.
The delay leaves DiMarco in an almost identical situation as at the Masters, where he battled Woods to a playoff after completing his weather-hit third round and a gripping final 18 holes on the Sunday.
"I'm just going to try and just keep the pedal on the floor and just try to keep making birdies," DiMarco said of his strategy for Sunday.
Bidding to become the first golfer from India to win a PGA Tour event, Atwal had been cruising along until disaster struck on the seventh.
After sending his tee shot into the deep rough, the 32-year-old could only manage a double-bogey while DiMarco drained a birdie for a three-stroke swing in his favour.
Defending champion Vijay Singh was two-under-par for the day with eight holes to play, moving the Fijian world number two into a group of five players tied for seventh place, four shots off the lead.
