"Congratulations to Sania Mirza for the victory in the US Open Mixed Doubles Finals. We are very proud of the achievement," Modi said.
Sania and Soares defeated American-Mexican pairing of Abigail Spears and Santiago Gonzalez 6-1, 2-6, 11-9 to win the title in New York Friday.
Retweeting the prime minister's tweet, she thanked him.
"Thank you very much sir...Look forward to meeting you at your convenience in the near future," she said.
The prime minister also congratulated Japanese tennis player Kei Nishikori for making it to the US Open Finals.
"Good news from the US Open continued with Kei Nishikori's exemplary win! My best wishes to this young sportsman for the Final," Modi said.