Oakland Classic: Francesca Jones battles injury in comeback win over Sinja Kraus

Britain’s third-ranked Jones broke into the top 100 last year and won two WTA 125 titles – a level below the main tour level.

Doctors previously told her she would not play professional tennis because she was born with a rare genetic disease.

Jones has ectodermal dysplasia of the external digits (EEC), which means she has three fingers and a thumb on each hand, three toes on her right foot and four on her left foot.

Jones struggled in the Auckland heat but fought back to save nine of 13 break points in just over two hours to advance.

“She just couldn’t perform in the first set and a half and I found it difficult to adjust to playing in the day compared to the evening. It’s a lot quicker,” Jones added.

Jones will face China’s seventh seed Wang Xinyu for a spot in the semi-finals.