Gopalan Balachandran, maternal uncle of US Senator Kamala Harris, said he had told her niece a day earlier that she was "going to win" to become the next US vice president.
US Democrat Joe Biden defeated incumbent Republican President Donald Trump in the closely-fought presidential election, according to US media projections.
Ms Harris, 56, who is of Indian origin, has become the first-ever woman vice president-elect of the US. She will also be the first Indian-origin, first Black and first African American vice president of the country.
Delhi-based Mr Balachandran said he was feeling "proud and happy", describing Kamala Harris as a fighter.
"Biden-Harris victory is what we wanted to see. And, given the numbers, I told Kamala yesterday that she is going to win," he said.
Joe Biden, the 77-year-old former vice president, will become the 46th president of the United States, the CNN reported, after a victory in Pennsylvania, the state where he was born put him over the 270 electoral votes needed to win.
"This election is about so much more than Joe Biden or me. It's about the soul of America and our willingness to fight for it. We have a lot of work ahead of us. Let's get started," Ms Harris tweeted.
She was born to two immigrant parents: a Black father and an Indian mother. Her father, Donald Harris, was from Jamaica, and her mother, Shyamala Gopalan, a cancer researcher and civil rights activist from Chennai.
Mr Balachandran had said that Ms Harris' nomination as the vice presidential candidate was a "historic moment", but it was not a surprise at all for him.
He said that she would script many firsts if she won and expressed the hope her top-level position would give Indians in the US "greater access" in interacting with the US administration.
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