Serena Williams of the US reacts during the first game of the third set against Kaia Kanepi of Estonia during the seventh day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JUSTIN LANE
Kaia Kanepi of Estonia reacts during a first set changeover as she plays Serena Williams of the US during the seventh day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JUSTIN LANE
Elina Svitolina of Ukraine hits a return to Anastasija Sevastova of Latvia during the seventh day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JASON SZENES
Karolina Pliskova of the Czech Republic reacts as she plays Ashleigh Barty of Australia during the seventh day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JOHN G MABANGLO
Ashleigh Barty of Australia hits a return to Karolina Pliskova of the Czech Republic during the seventh day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JOHN G MABANGLO
Sloane Stephens of the USA smiles after defeating Elise Mertens of Belgium during the seventh day of the US Open Tennis Championships at the Arthur Ashe Stadium in the USTA National Tennis Center in Flushing Meadows, New York, USA, 02 September 2018. The US Open runs from 27 August through 09 September. EPA-EFE/JASON SZENES