Sania Mirza [ Images ] and her American partner Bethanie Mattek [ Images ] bowed out of the WTA East West Bank Classic tournament after retiring midway through their semifinal match in Los Angeles on Saturday.

Second seeds Sania and Mattek were trailing 2-6, 1-2 when they pulled out of their match against the Czech pair of Eva Hrdinova and Vladimira Uhlirova in the tier II USD 600,000 hard court event.

The Indo-American pair had to pull out after Mattek complained of a low back injury.

Meanwhile, Hrdinova and Uhlirova will take on top seeds Chan Yung-Jan and Chuang Chia-Jung, who beat number four seeds Lisa Raymond [ Images ] and Samantha Stosur [ Images ] in a match tie-break, 7-6 (3), 3-6, 10-7.