SYDNEY (Reuters) - Eamon Sullivan broke the 50 metres freestyle world record for the second time in 24 hours on Friday, enhancing his claims as the early favourite to win the gold medal in Beijing.

The 22-year-old from Western Australia stormed down Sydney's Olympic pool in 21.28 seconds to win the final and slash 0.13 off the previous record he set in Thursday's semi-finals.

Sullivan broke Alex Popov's long-standing world record last month but lost it to Alain Bernard of France at the European championships last weekend.

However, after posting the second and third fastest times for the 100, he regained his title as the fastest man in the water by breaking the 50 record.

"Hopefully they will be shaking in their boots," Sullivan said in a poolside interview.

"It's pretty funny for me the 50, I usually cannot remember anything. It's just such a blur and a rush of energy that it all happens so fast."

Sullivan's record was the seventh in as many days at the Australian trials.

His girlfriend Stephanie Rice broke the 200 and 400 individual medley records, Libby Trinkett (nee Lenton) regained the 100 freestyle mark and Sophie Edington and Emily Seebohm took turns in breaking the 50 backstroke record.

(Editing by Peter Rutherford)