Scotsman Richie Ramsay thrived in the cold and wet Swiss Alps, shooting a 64 to move into the lead at 11 under after three rounds of the European Masters.
Ramsay fired six birdies and didn't drop a shot to hold a one-stroke lead from fellow Scot Paul Lawrie (67) and Danny Willett (68) of England.
"It was a nice and steady round," said the 29-year-old Ramsay, who was at the first tee when fog suspended play in the morning. "It sounds simple, it's harder to do."
Overnight leader Julien Quesne of France is a further shot back after going round in 70. That counted as level on the usual par-71 Severiano Ballesteros course after heavy rain forced organizers to reduce the soaked par-4 sixth hole to a par-3.
Fog then rolled in approaching midday and delayed play for nearly two hours as the leading groups prepared to start their rounds.
Lawrie, seeking his second straight title after victory at Gleneagles, Scotland, last week, led until going out of bounds off the tee at the par-5 14th.
The European Ryder Cup player made a double-bogey seven, and acknowledged being "a bit frustrated" with his 67.
"I played lovely again today and could easily have been four or five shots better," Lawrie said. "But one behind now, I would have taken that at the start of the week."
Ramsay, who placed sixth behind his fellow Aberdeen native at Gleneagles, has never led a European Tour event after three rounds.
"54-hole leader sounds good but 72-hole leader sounds even better," said Ramsay, whose only victory came at the 2010 South African Open.
Still, 21 players will tee off Sunday within five shots of the lead on a course which plays short in the thin mountain air.
Joost Luiten of the Netherlands trails by four shots after firing the lowest score of the day, a 63 that included three eagles.
David Lynn of England, the runner-up behind Rory McIlroy at the United States PGA Championship last month, moved to 6 under with a 65.
The 2009 winner here, Alexander Noren, had perhaps the strangest round of an interrupted day. The Swede started early and went out in 30, but after the fog delay came home in 39 to fall back to 1 under.