Niculescu had taken the first set 7-5 and was leading 3-2 in the second when Zvonareva, the sixth seed, called it quits, the second time she was doing so in as many weeks because of the same problem.

Last week in Pattaya, Zvonareva quit during her quarter-final match with another Romanian, Sorana Cirstea, who was taking on Australia's Samantha Stosur in Doha on Wednesday.

Earlier on Wednesday the fourth seeded Agnieszk Radwanska of Poland thrahed Great Britain's Anne Keothavong 6-1, 6-2, while French fifth seed Marion Bartoli also had it easy, beating Spaniard Anabel Madinah Garrigues 6-2, 6-0.

Serb Jelena jankovic also bowed out, falling to Israeli Shahar Peer 7-6 (7/4), 6-2.
 
 

In Indian Wells,   California, Kim Clijsters announced Tuesday that she has withdrawn from next month’s BNP Paribas Open because of an injury to her left ankle.

Clijsters said in a statement that she is disappointed she won’t be playing in the tournament, saying she has great memories of Indian Wells.

The Belgian plans to retire at the end of the season. Clijsters has already retired once — in 2007 — but was tempted back in 2009 and has since won three Grand Slam titles.

She won the Australian Open a year ago but the remainder of the season was marred by shoulder, wrist and abdominal injuries. A twisted ankle almost curtailed the defense of her Australian Open title last month. Clijsters lost to eventual champion Victoria Azarenka.