Elena Rybakina of Kazakhstan serves during the women's singles semifinal match against Kristyna Pliskova of the Czech Republic at WTA Shenzhen Open tennis tournament in Shenzhen, south China's Guangdong Province, Jan. 10, 2020. (Photos: Xinhua/Liang Xu)

Kristyna Pliskova of the Czech Republic returns a shot during the women's singles semifinal match against Elena Rybakina of Kazakhstan at WTA Shenzhen Open tennis tournament in Shenzhen, south China's Guangdong Province, Jan. 10, 2020.

Elena Rybakina of Kazakhstan returns a shot during the women's singles semifinal match against Kristyna Pliskova of the Czech Republic at WTA Shenzhen Open tennis tournament in Shenzhen, south China's Guangdong Province, Jan. 10, 2020.

Kristyna Pliskova of the Czech Republic serves during the women's singles semifinal match against Elena Rybakina of Kazakhstan at WTA Shenzhen Open tennis tournament in Shenzhen, south China's Guangdong Province, Jan. 10, 2020.

Kristyna Pliskova of the Czech Republic returns a shot during the women's singles semifinal match against Elena Rybakina of Kazakhstan at WTA Shenzhen Open tennis tournament in Shenzhen, south China's Guangdong Province, Jan. 10, 2020.