Zvonareva won the Prague Open earlier this month after losing to Serena Williams in the final at Charleston, South Carolin, in her previous tournament. In between, Zvonareva posted a three-set win over Vania King on clay to clinch victory for Russia in the Fed Cup semifinals against the United States.
Zvonareva improved to 32-7 overall this year.
Eleventh-seeded Agnes Szavay of Hungary routed China's Yan Zi 6-1, 6-1; and Italy's top player, No. 17 Francesca Schiavone, got by Lucie Safarova 6-4, 7-5 on an overcast day at the Foro Italico.
Also advancing were: Virginie Razzano, Virginia Ruano Pascual, Monica Niculescu, Anabel Medina Garrigues and Caroline Wozniacki.
Australia's Samantha Stosur marked her return to the tour with a 6-3, 6-2 victory over 42nd-ranked Michaella Krajicek. Stosur will next face seventh-seeded Venus Williams.
Stosur, a former doubles No. 1, had been out for several months due to illness. She upset two-time Rome champion Amelie Mauresmo in the second round last year.
Mauresmo withdrew Sunday with a rib injury.
Top-ranked Justine Henin also pulled out, citing fatigue, and Dinara Safina withdrew due to a back injury Monday, one day after winning the German Open.
Ana Ivanovic and Maria Sharapova are seeded No. 1 and No.2. The top eight seeded players have first-round byes in this clay-court warmup for the French Open, which begins May 25.
Ivanovic did not play at the Foro Italico the past two years due to injuries.
"I was really disappointed the last two years. I'm really excited to be back here, and hopefully I can actually step on the court and play,'' Ivanovic said, adding that Rome is her favorite city in Europe. "I love this place, and I hope I can stay a long time.''
Ivanovic reaches German Open semifinal
German teen Lisicki upsets Peer in German Open
