Story highlights Tim Kaine revealed a conversation he had with Hillary Clinton in April 2014

He cited Clinton's status as the potential first female president

Washington (CNN) Hillary Clinton has more money, a much longer political resume, a better-organized campaign than Donald Trump and a lead in national polls.

Yet Clinton's running mate, Tim Kaine, says she's the underdog.

In an interview on CBS' "Face the Nation" Sunday, the Virginia senator recalled an April 2014 conversation with Clinton, who he said had not yet decided whether she would run for president.

He cited the reality that Clinton would be the first woman elected president.

"I said, 'No matter what the polls say and no matter what you see in that editorial, consider yourself the underdog. You're trying to do something that's never been done.' I said, 'If it had been easy for a woman to be president in this country, we would have had a woman president of the country. So consider yourself the underdog until they call you the winner,'" Kaine told host John Dickerson.

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