Hingis set to announce retirement

Swiss star Martina Hingis is expected to retire for a second time on Thursday, BBC Sport understands.

The former world number one, 27, has struggled to recover from a string of injuries and health-related problems.

She called an early end to her season last month because of hip problems but had vowed to return to action.

The five-time Grand Slam champion first retired in 2003 because of persistent ankle injuries before returning to top flight tennis at the start of 2006.

Following her return to the tour Hingis surprised her doubters by winning three more titles.

She ended 2006 ranked seventh in the world and is currently ranked 19th.

Source: BBC Sport