Former world number one Ana Ivanovic was the first major casualty of the US Open as the Serbian seventh seed fell 6-3, 3-6, 6-3 to Dominika Cibulkova in the opening match at Arthur Ashe Stadium yesterday. The 50th-ranked Cibulkova of Slovakia seized the advantage with a service break in the fourth game of third set for a 3-1 lead and consolidated it with a backhand drop shot to make it 4-1 against the former French Open champion.Cibulkova will next face American qualifier Jessica Pegula, a 7-5 6-3 winner over Belgian Alison Van Uytvanck. Other early matches on the women's side went according to script as 13th-seeded Russian Ekaterina Makarova dismissed Brazil's Teliana Pereira 6-3, 6-3 and 15th seed Agnieszka Radwanska of Poland crushed Czech Katerina Siniakova 6-2,6-3.