|Agnieska Radwanska is the highest seed on either |
side of the draw to lose in the first four days of competition
To my mind, the biggest upset was Ana Ivanovic losing in the 2nd round to Karolina Pliskova despite having won the most matches on tour of any active player and playing quite well during the American hard court summer season, losing the finals of Cincinnati to Serena Williams.
Another surprising loss by a player who was playing well coming into Flushing Meadows was Svetlana Kuznetsova's departure in the first round.
The upset that is getting probably the most press is 15-year-old CiCi Bellis 3-set victory over 2014 Australian Open finalist Dominika Cibulkova. Bellis is more than 2 years younger than any other competitor in the main draw of either the men's or women's singles competition at this year's U.S. Open. She won her right to play by winning the Under-18 championships, the youngest payer to do so since Lindsay Davenport.
Serena and Venus Williams are safely through to the 3rd round. Also, 2014 French Open champion Maria Sharapova and 2014 Wimbledon champion Petra Kvitova did not get upset in their first two matches. Sharapova faces Sabine Lisicki in the 3rd round while Venus faces Sara Errani.