Jones of GB fights an injury in a comeback victory in Auckland

Jones defeated world number 15 Emma Navarro in three sets on Monday, marking the biggest victory in her career.

After calling for the physiotherapist twice, the 25-year-old appeared to be experiencing the aftereffects when she lost to Austrian qualifier Sinja Kraus in a set and a break.

She rebounded, though, and won 12 of the next 14 games to win 1-6 6-4 6-1.

Jones said, "I'm actually really relieved that's over" to New Zealand's Sky Sport.

"It's difficult to get back up after defeating someone like Emma in the first round both mentally and physically especially under these circumstances.

"I'm glad I got through that."

After winning two WTA 125 titles the tier below the main tour British number three Jones entered the top 100 last year.

Because she was born with a unique genetic abnormality physicians had previously advised her not to play tennis professionally.

Jones has three fingers and a thumb on each hand three toes on her right foot and four toes on her left foot due to Ectrodactyly Ectodermal Dysplasia (EEC).

Despite the intense heat in Auckland Jones fought back to progress in just over two hours saving nine of her thirteen break points.

"It was incredibly difficult for me to adjust to playing during the day as opposed to at night, and she was unplayable for the first set and a half. It's much faster," Jones continued.

Jones will compete against Wang Xinyu the seventh seed from China to advance to the final four.

Gauff guides the US to the semifinals of the United Cup

In other news Coco Gauff guided the United States the reigning champions to the United Cup mixed team tournament semifinals.

After fellow countryman Taylor Fritz lost 6-4 7-5 to Stefanos Tsitsipas world number four Gauff defeated Maria Sakkari of Greece 6-3 6-2.

After that Gauff and Christian Harrison faced Sakkari and Tsitsipas in a superb deciding mixed doubles match which the American duo won 4-6 6-4 10-8.

On Saturday they will play either the hosts Australia or Poland in the last four.

With a quick 6-3 6-2 victory over Suzan Lamens of the Netherlands Wimbledon champion Iga Swiatek helped Poland advance to the quarterfinals.

Earlier Hubert Hurkacz defeated Tallon Griekspoor 6-3 7-6 (7-4) after recovering from a protracted knee ailment.