Defending champion Zheng Jie has crashed out of the ASB Classic tennis tournament with a 7-5 6-1 defeat to American Jamie Hampton.

Zheng, the world No.26 and fourth seed, was competitive in the first set but lost the last two games to lose the set.

The American continued to gain confidence as she unleashed some precision groundstrokes which the Chinese woman frequently failed to retrieve.

It is the second consecutive year the defending champion has lost in the first round after 2011 champion Greta Arn suffered the same fate in 2012.

Hampton will play New Zealander Marina Erakovic or Canadian Stephanie Dubois in the second round.

Earlier, Russian Elena Vesnina credited her experience with Auckland’s wind to help her advance for the fifth consecutive time.

Vesnina had a tough first set against 18-year-old Canadian wildcard Eugenie Bouchard, but adapted to the conditions best in the second set to win 7-5 6-3.

“I’m an old lady compared with Eugenie so I have to have some experience to help me and, last year when I played, we had exactly the same situation and I didn’t change my serve,” the 26-year-old Russian said.

“Now maybe I learned that lesson. I started tossing the ball a little bit lower and it helped me a lot.”

Fast-improving Dutchwoman Kiki Bertens looked a player to watch after she beat two-time grand slam champion Svetlana Kuznetsova.

The 21-year-old Bertens lost a first-set tiebreaker against Kuznetsova, who came into the tournament unseeded after missing the second half of 2012 through injury.

But the powerful Bertens kept her nerve, handling the wind well to beat Kuznetsova 6-7 6-2 7-5.

Christina McHale was the first seed to drop out of the tournament, losing 6-4 6-1 to Pauline Parmentier of France, who didn’t allow the American a break point.

Third seed Yanina Wickmayer of Belgium is safely through, beating Magdalena Rybarikova 7-6 6-2.

Other winners were Eleni Daniilidou of Greece, Johanna Larsson of Sweden, Simona Halep of Romania and Kirsten Flipkens of Belgium.