SYDNEY (Reuters) - American Lee Williamson shot a superb opening round of seven-under-par 65 on Thursday to lead the Australian Open by two shots.

The 28-year-old from Indiana posted 10 birdies in his round and would have broken Greg Norman and Steve Elkington's course record of 64 had he not taken a triple bogey on the ninth hole.

"I did not figure I would make 10 birdies in the first round," Williamson told reporters.

"I think I scored better than I played, not that I played poorly. I putted well and I pitched in twice."

Former two-time champion Robert Allenby fired a 67 to finish the day in a three-way tie for second with fellow Australians Andrew Bonhomme and Kim Felton, one shot ahead of a group including 2006 U.S. Open champion Geoff Ogilvy.

(Reporting by Julian Linden; Editing by Greg Stutchbury)