Thailand's Kiradech Aphibarnrat was closing in on a first European Tour title when play was suspended at the Maybank Malaysian Open.
The tournament had already been reduced to 54 holes following thunderstorms on each of the first three days, with the leaders managing just two holes of their third rounds on Saturday.
And the final group had just teed off on the 16th when the sirens sounded to signal another approaching storm and the threat of lightning in the area at Kuala Lumpur Golf Club.
Aphibarnrat, fourth in the Avantha Masters last week, was 13 under par and one clear of Italy's Edoardo Molinari, who had fortunately completed his round of 67 to set the clubhouse target just before play was halted.
“It’s mixed emotions because I’m very happy to have a good week for the first time in a long time,” said Molinari, for whom this was a first cut made since returning from a wrist injury.
“The swing changes are starting to pay off which is surprising because I thought it would take a lot longer, but I’m disappointed because I had a lot of chances on the back nine. The 18th is only the second fairway I missed all day which is very disappointing.
“I don’t think 12 under will be good enough. I felt if I birdied the last I might have won outright because it puts a lot of pressure on the guy coming up behind, but unfortunately I think I’ll be one or two short.”
Denmark's Anders Hansen was a shot further back after completing a 66 before heading off to watch the Malaysian Formula One Grand Prix, while France's Victor Dubuisson and China's Wu Ashun were also 11 under on the course.
Tournament officials announced that play would resume at 3:15pm local time, a delay of just over two hours.