Sept 3 (Reuters) - Order of play on the main show courts on the sixth day of the U.S. Open on Saturday (play starts at 1500 GMT/11 AM ET unless stated, prefix number denotes seeding): ARTHUR ASHE STADIUM (1600 GMT/12 PM ET) 10-Petra Kvitova (Czech Republic) v 17-Maria Sakkari (Greece) 1-Novak Djokovic (Serbia) v Kei Nishikori (Japan) 1-Ash Barty (Australia) v Shelby Rogers (U.S.) 4-Alexander Zverev (Germany) v Jack Sock (U.S.) LOUIS ARMSTRONG STADIUM Greet Minnen (Belgium) v 6-Bianca Andreescu (Canada) 11-Belinda Bencic (Switzerland) v 23-Jessica Pegula (U.S.) 17-Gael Monfils (France) v 13-Jannik Sinner (Italy) Lloyd Harris (South Africa) v 7-Denis Shapovalov (Canada) Varvara Gracheva (Russia) v 14-Anastasia Pavlyuchenkova (Russia)