The 29-year-old's 7-5 6-3 win over French qualifier Anne-Gaelle Sidot took her career earnings to $20,348,992 (£12.251m) and set up a semi-final meeting with Dominique Van Roost of Belgium.

She moves ahead of Martina Navratilova , who won $20,344,061 during her career, in the all-time list, but she insisted the feat was "not all that important" to her.

Graf was world number one for 377 consecutive weeks but injuries have dogged her in recent years and she is playing her first tournament for two months following a wrist operation.

"Tennis is my life. I need that unique feeling you get when you're out there playing. My injuries have helped me look at all this from a distance and it made me realise how much I really love this sport," she said.

Sidot broke in the opening game and served for the first set before Graf, who has a 23-0 record in Leipzig and has won the event four times, finally found the range with her groundstrokes.

"It took me three-four games to loosen up," she admitted.

Second seed Nathlaie Tauziat reached the last four with a 6-3 6-4 victory over Anke Huber of Germany and she now faces Romanian Irina Spirlea, an easy 6-1 6-1 winner over Sarah Pitkowski.

Top ten women's earners: