(CNN) Hillary Clinton responded to the tightening race with Bernie Sanders on Thursday by arguing early polls that showed her with a sizable lead were "artificial."

Clinton, in an appearance on "The Tonight Show," agreed that she and Sanders are "in a tight race," a fact that she finds "pretty exciting."

After noting she and Sanders are close, host Jimmy Fallon reminded Clinton that she once "had a 20-point lead at one point."

"That is really artificial, all of those early soundings and polls," Clinton said. "Once you get into it, this is a Democratic election for our nominee and it gets really close, exciting. And it really depends upon on who can make the best case that you can be the nominee to beat whoever the Republicans put up and try to get your folks who support you to come out."

She added, "I find it pretty exciting. This is not a job they give away. You really do have to work hard for. It is the hardest job in the world, so, I get up everyday and go right at it."

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