Iga Swiatek's Poland has reached the semi-final of the Billie Jean King Cup for the first time in history.
Coco Gauff's biggest payday in tennis came at the WTA Finals in Riyadh when she defeated Zheng Qinwen 3-6, 6-4, 7-6(2) to earn a cheque of $4.805m.
Despite beating beat Daria Kasatkina, Iga Swiatek was knocked out of the WTA Finals in Riyadh on Thursday.
Coco Gauff sealed her place in the WTA Finals semi-finals thanks to a shock win over long-term rival Iga Swiatek on Tuesday.
The Pole announced two weeks ago that she had split from Tomasz Wiktorowski after three hugely successful years together in which she won four grand slam titles.
Iga Swiatek picked herself up following the disappointment of missing out on gold to claim the bronze medal in the Olympic women's singles.