LONDON (Reuters) - Wimbledon is well-known for its unpredictable weather, with rain interrupting play an all-too regular fixture at the annual grand slam tennis tournament.

But the club, which is hosting Olympic tennis, came unstuck on Saturday because of wind as a sharp gust whipped the U.S. flag off its rail mid-women's singles victory ceremony to a gasp from the 15,000 capacity Centre Court crowd.

Gold medal winner Serena Williams, who moments earlier had been beaming with delight as the stars and stripes were hoisted to the sound of the U.S. national anthem, looked momentarily bemused as the flag fluttered to the floor.

"It was so windy I was surprised they didn't all fall off," she said. "I was so in the moment of just seeing my family and the medal."

It is not the first flag fiasco for London 2012 organizers, with the South Korean flag shown on a video screen when North Korea's women's soccer team met Colombia in Glasgow last week.

(Reporting by Kylie MacLellan)