China's Zheng Jie holds the trophy after beating Italy's Flavia Pennetta (L) during the singles final of the ASB Classic international tennis tournament in Auckland, Jan 8, 2012. Zheng won the match after Pennetta retired injured.[Photo/Agencies]

AUCKLAND - China's Zheng Jie came back from behind to claim the championship at the 2012 ASB Classic women's tennis tournament in Auckland on Sunday.

Playing indoors after the original scheduled match day was washed out by the rain Saturday, Italy's Flavia Pennetta yielded the game when she pulled out, complaining of a back injury while trailing in the third set.

It was the first WTA title for the unseeded Zheng since winning in Estoril and Stockholm in 2006.

Jie went down 2-6 in the first set, but took control of the game when the fourth seed Italian started complaining of a back injury.

Pennetta's strong serves secured five consecutive points in the first set and she was soon up 3-1.

The first signs of trouble came when the Italian called a medical time out for a problem with her back while she was leading 5-2.

Despite the problem, Pennetta's play appeared to be unaffected and she held serve to claim the set.

However, the second set proved to be her breaking point and Zheng took four games in a row.

Fearing she would aggravate her injury, Pennetta called it quit early in the third set, when Zheng was leading 2-0.

Zheng secured her place in the finals by defeating number 3 seed Svetlana Kuznetsova of Russia, 2-6, 6-3, 6-3 on Friday.

Pennetta defeated Germany's Angelique Kerber 6-1 6-2 in under an hour the same day.