KEY BISCAYNE, FL - MARCH 28:  Serena Williams of the United States walks off court after her three set defeat against Svetlana Kuznetsova of Russia in their fourth round match during the Miami Open Presented by Itau at Crandon Park Tennis Center on March 28, 2016 in Key Biscayne, Florida.  (Photo by Clive Brunskill/Getty Images)