Two-time champion Venus Williams defeated in third round of U.S. Open . Serena Williams, who has won the last three majors, is seeded No. 1 for first time. No . 13 Sara Errani wins epic encounter 6-0 0-6 7-6 . Qualifier Mirjana Lucic-Baroni knocks out second seed Simona Halep . Roger Federer and Maria Sharapova , also former winners at Flushing Meadows , hope to stay the course later on Friday . The former Croatian teenage star describes her shock victory as `` incredible ''
Two-time champion Venus Williams defeated in third round of U.S. Open . Serena Williams, who has won the last three majors, is seeded No. 1 for first time. No . 13 Sara Errani wins epic encounter 6-0 0-6 7-6 . Qualifier Mirjana Lucic-Baroni knocks out second seed Simona Halep . The former Croatian teenage star describes her shock victory as `` incredible ''