England's Paul Casey survived the notorious Melbourne weather to shoot a seven-under-par round of 65 and hold the overnight lead at the Heineken Classic.
The 25-year-old teed off in the teeming rain and was putting on the 11th, his second, when play was suspended for 90 minutes as the greens became waterlogged.
But once the fickle Melbourne weather had turned warm and sunny again, Casey put together an almost faultless display to shoot eight birdies and claim the outright lead at Royal Melbourne.
Spaniard Santiago Luna, who made a storming start with five birdies in his first six holes, finished a shot further back on six under par.
English pair Warren Bennett and Gary Evans, who shot to fame with a fifth place finish at the 2002 Open championship, were tied on five under par with Australians Peter Fowler and Peter Lonard, whose round of 67 was bogey free.
Home favourite Greg Norman slumped to a one-over round of 73, while tournament favourite Ernie Els also struggled.
The South African, coming off the back of two victories and a second place in his last three tournaments, bogeyed his first and had to fight to remain at level par.
But the suspension in play, called by tour operations manager Gus Seeback at 1.33p.m. local time, allowed the defending champion the opportunity to "regroup" - and he eventually battled to finish at two under par.
Meanwhile, Nick Faldo eventually clawed back to three under after dropping three shots in two holes just as the winds picked up.
Casey, a member of England's World Cup team and the victorious Seve Trophy side of last year, could not remember ever having led a professional tournament after the opening round.
"I have done it plenty of times as an amateur and it is something I would like to do more," he said. "I always seem to make a charge and do all the work at the end. It would be nice to make it easier."
Ireland's Peter Lawrie struggled to an opening 79. PA