Serena Williams has announced her retirement from tennis

It's a farewell for Serena Williams as the tennis champion announced she would retire following this year's US Open. Speaking to the New York Post, United States Tennis Association (USTA) spokesman Chris Widmaier said the demand for tickets hit a point no one could have predicted.

"You talk about the Serena effect, it's like a tsunami," Widmaier told the Post.

"Since people have learned of the news, we've sold, as of 3 p.m., 13,000 tickets to the Open, including 4,500 or thereabouts for Opening Night.'

When clarifying, Widmaier called it, 'a spectacular day. In fact, it may be unprecedented.'

There has been particular interest in Williams' first match, with tickets that retail for $35 in the upper deck being re-sold on the second hand market for $7,000.

On top of that demand, there is no guarantee that Williams even plays on the first night, with the draw set for the Thursday prior to the tournament.