Alison Riske of the United States celebrates during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Petra Kvitova of the Czech Republic competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Petra Kvitova of the Czech Republic competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Alison Riske of the United States competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Alison Riske of the United States competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Petra Kvitova of the Czech Republic competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Alison Riske of the United States serves during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Petra Kvitova of the Czech Republic competes during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)

Alison Riske of the United States serves during the women's singles semifinal between Alison Riske of the United States and Petra Kvitova of the Czech Republic at the 2019 WTA Wuhan Open tennis tournament in Wuhan of central China's Hubei Province, on Sept.27, 2019. (Xinhua/Xiong Qi)