Sania Mirza and her Zimbabwean team-mate Cara Black have crashed out of the WTA Dubai Open Tennis Championships.In the opening round yesterday, the fourth seeded Indo-Zimbabwean pair lost to the Czech duo of Andrea Hlavackova and Lucie Safarova, 6-7, 7-5, 9-11.In the Women's Singles, World Number One Serena Williams of the United States has advanced to the quarterfinals. In the second round, Serena defeated Ekaterina Makarova of Russia, 7-6, 6-0, to book a quarterfinal berth.