not at her best due to a back injury.
The top seeded Indo-Swiss pair lost 3-6 3-6 to Croatia's Petra Martic and Stephanie Vogt from Liechtenstein in the first round of the USD 731,000 event.
It was first defeat for Sania and Martina since joining forces.
In an incredible run of 14 straight wins, they won three back-to-back-to-back titles in Indian Wells, Miami and Charleston.
Sania and Martina lost three straight games from 3-all to drop the first set.
They made progress in the second set, going up 2-0 with an early break but the first-time pairing of Martic and Vogt fought back, made it 2-all, and easily clinched the set and the match.
Image: Martina Hingis and Sania Mirza
Photo: Getty Images