NEW YORK, USA - AUGUST 31: Venus Williams of USA walks out on court ahead of her match against Serena Williams (not seen) of USA during US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Serena Williams of USA walks out on court ahead of her match against Venus Williams (not seen) of USA during US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Serena Williams of USA in action against Venus Williams (not seen) of USA in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Serena Williams of USA in action against Venus Williams (not seen) of USA in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Venus Williams of USA in action against Serena Williams (not seen) of USA in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Serena Williams of USA in action against Venus Williams (not seen) of USA in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Serena Williams of USA in action against Venus Williams (not seen) of USA in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Venus Williams (R) of USA congratulates Serena Williams (L) of USA after competing in the Women's Singles round three match within the US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Karen Khachanov of Russia competes against Rafael Nadal (not seen) of Spain during Us Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Rafael Nadal of Spain competes against Karen Khachanov of Russia (not seen) during Us Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Karen Khachanov of Russia competes against Rafael Nadal of Spain (not seen) during Us Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Rafael Nadal of Spain gestures as he competes against Karen Khachanov of Russia (not seen) during US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Rafael Nadal of Spain celebrates after winning against Karen Khachanov (not seen) of Russia during US Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )
NEW YORK, USA - AUGUST 31: Karen Khachanov of Russia competes against Rafael Nadal (not seen) of Spain during Us Open 2018 tournament in Arthur Ashe Stadium in Flushing, New York, United States on August 31, 2018. ( Mohammed Elshamy - Anadolu Agency )