Having saved two match points to take home the Tokyo title last weekend, Black and Mirza have strengthened their aura of invincibility with three comfortable wins in the Chinese capital. The latest of these came against Chan Yung-Jan and Zheng Jie, who after some early resistance were swept aside, 64 61.
However, after a surrendering the break and then the set it was one-way traffic with Black and Mirza wrapping up victory after little over an hour on court.
Chan and Zheng, who had points for a 5-3 and 5-4 lead, were left ruing their missed opportunities. "We started well and had a 4-2 lead in the first set," Zheng said. "The first set we played was really close and we had many chances in the games at the end, but at that point sometimes you need a little bit of luck and things to go your way.
"Then after we lost the first set, I think that Sania and Cara got a lot more confident and on their current form it's not easy against them."
Next up for Black and Mirza will be top seeds Sara Errani and Roberta Vinci, after they saw off the challenge of Kristina Mladenovic and Flavia Pennetta, 63 64. Also advancing were No.2 seeds Hsieh Su-Wei and Peng Shuai, 62 76(4) winners over Raquel Kops-Jones and Abigail Spears, and Vera Dushevina and Arantxa Parra Santonja, who defeated Daniela Hantuchova and Lisa Raymond, 64 75.