TAIPEI (AFP) - Hsieh Su-wei will become Chinese Taipei's first tennis world No. 1 when she joins her partner Peng Shuai at the top of the doubles rankings, the Women's Tennis Association (WTA) said on Friday.

Hsieh and China's Peng, who are into the Madrid Open semi-finals, will be listed as joint world No. 1s in the new rankings released on Monday.

"Reaching No. 1 in the world is a great feeling," said Hsieh, 28. "We have been working really hard as a team.

"I was very proud Peng reached No. 1 earlier this year and now I am happy we can share it."

Hsieh and Peng have won 11 WTA titles together and have never lost a final. They are the 10th doubles team to be listed as co-No. 1.

"It is a great accomplishment for Hsieh Su-wei to join Peng Shuai as co-world No. 1s," said WTA chairman and CEO Stacey Allaster.

"Not only are Hsieh and Peng a great doubles team, but they are also an inspiration to the fans throughout the Asia-Pacific region."

Hsieh and Peng, who reached the top doubles ranking in February, will face Spain's Garbine Muguruza and Carla Suarez Navarro in the Madrid semi-finals on Friday.