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FILE - In this Thursday, Sept. 8, 2016 file photo, Serena Williams returns a shot to Karolina Pliskova, of the Czech Republic, during the semifinals of the U.S. Open tennis tournament, in New York. Williams says she “won’t be silent” about the killing of black men by police officers. Williams wrote on Facebook on Tuesday, Sept. 27, 2016, that she was inspired to speak out after asking her black 18-year-old nephew to drive her to a meeting. (AP Photo/Darron Cummings, File)

U.S. Open 2011

The U.S. Open is underway in Flushing Meadows, New York.