Mirza's previous mixed doubles titles came at the 2009 Australian Open and the 2012 French Open. She lifted the trophy with compatriot mahesh Bhupathi on both occasions.
Soares, on the other hand, claimed his second US Open mixed doubles title after 2012 when he partnered Russia's Ekaterina Makarova.
Sania Mirza was recently attacked by right-wing politicians in India after she was chosen as the brand ambassador of Telangana, which was recently carved out of Andhra Pradesh. She was described as the daughter-in-law of Pakistan for her marriage with Pakistani cricketer Shoaib Malik, which had left her in tears during a television interview.