Ivanovic beat Svetlana Kuznetsova in last year's finale.
Agnieszka Radwanska of Poland defeated Canadian Aleksandra Wozniak 6-1, 6-4, and Italian Flavia Pennetta, who next plays Ivanovic, beat American Angela Haynes 4-6, 6-4, 6-1.
Spaniard Nuria Llagostera Vives beat Russian Alisa Kleybanova 7-6 (7-2), 6-3; Hungarian Agnes Szavay beat German Kristina Barrois 6-3, 6-4; and Austrian Sybille Bammer beat Russian Vera Dushevina, 6-1, 6-3.
Members of Congress to keep receiving porn magazine
Putin thinks Obama would save him if he were drowning