New York: Indian ace Sania Mirza's mixed doubles campaign failed start at the US Open as she lost her first round match in partnership with Bruno Soares to Andrea Hlavackova and Lukasz Kubot on Friday.

The top seeded pair fell to the unseeded duo, losing 3-6, 3-6 in a contest lasting 65 minutes.

Meanwhile World No.1 Serena Williams, too, had to fight it out against an inspired Bethanie Mattek-Sands in the third round of women’s singles, as she lost the first set 6-3, and was 5-3 behind in the second set, before winning it 7-5. Thereafter, she won consecutive six games in the third set to win it 6-0.

Now Serena will play No.19-seeded Madison Keys, who overpowered No.15 seed Agnieszka Radwanska, 6-3, 6-2. Williams beat Keys in their only previous meeting.