Karolina Pliskova of the Czech Republic hits a return to Angelique Kerber of Germany during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/JOHN G. MABANGLO

Angelique Kerber of Germany hits a return to Karolina Pliskova of the Czech Republic during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/CJ GUNTHER

Karolina Pliskova of the Czech Republic hits a return to Angelique Kerber of Germany during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/VINCENT LAFORET

Angelique Kerber of Germany hits a return to Karolina Pliskova of the Czech Republic during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/DANIEL MURPHY

Angelique Kerber of Germany (R) embraces Karolina Pliskova of the Czech Republic after the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/DANIEL MURPHY

Angelique Kerber of Germany celebrates with family members after defeating Karolina Pliskova of the Czech Republic during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/JOHN G. MABANGLO

Angelique Kerber of Germany (R) and Karolina Pliskova of the Czech Republic after the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/JOHN G. MABANGLO

Angelique Kerber of Germany celebrates with the championship trophy after defeating Karolina Pliskova of the Czech Republic during the women’s final on the thirteenth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 10 September 2016. The US Open runs through September 11. EPA/JUSTIN LANE