Bernie Sanders' ever-increasing poll numbers neither surprise nor threaten her, Democratic front-runner Hillary Clinton said on Jan. 14; rather, they will make the race for their party's 2016 White House nomination "pretty exciting."

On the day a new Des Moines Register poll put the Vermont senator and the former secretary of state at a statistical tie in the crucial, first-in-the-nation caucus state of Iowa, Clinton told host Jimmy Fallon on the "Tonight Show" that her earlier leads in surveys had not truly reflected reality.

"That is really artificial, all of those early soundings and polls," the wife for former President Bill Clinton explained. "Once you get into it, this is a Democratic election for our nominee and it gets really close, exciting."

'This is not a job they give away'

Clinton added that voters were only now taking a closer look at candidates and evaluating who was in the strongest position to win the general election in November.

"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 said. "This is not a job they give away. You really do have to work hard for it and it is the hardest job in the world so I get up every day and go right at it."

Pollster: Focus on issues favors Sanders

But Iowa pollster J. Ann Selzer told Bloomberg that many voters tend to be concerned about questions beyond electability, which explains why Sanders has been on the rise recently.

"Democrats are much more likely than Republicans to say this is an election about issues, rather than leadership. That really explains the division in the party," Selzer noted.

"Half of those who say this election centers on issues support Bernie Sanders, versus 37 percent for Clinton. Among those who say the election is about leadership, it's just the opposite. Half say Clinton is their first choice, versus 29 percent for Sanders," the pollster analyzed.