"The Barack Obama magic on Election Day has not carried over to the run-off," Ensign said.
Polls are scheduled to close at 7pm EST. Polling stations across the Peach State reported low voter turnout Tuesday, which would likely hurt Martin who was bolstered by the high-voter turnout inspired by Democratic presidential candidate Barack Obama last month.
If Chambliss wins, he will shatter the Democrats hopes of attaining a 60-seat supermajority. A run-off was triggered after the November 4 election because neither candidate secured the majority of the votes, Chambliss won 49.8 percent to Martin's 46.8 percent. Libertarian candidate Allen Buckely took 3.8 percent of votes.
A WSB-TV poll conducted over the weekend gave Chambliss a 4-point edge of 50 percent to 46 percent over Martin.
Ensign attributed an anticipated GOP win to a "far superior" ground game and Sarah Palin's appearances around the state on Monday.
"In a run-off election it's about turning your voters out," Ensign told reporters in a late afternoon conference call. "She was able to get a lot of people excited to make sure they would focus on that race...because of her celebrity she was able to bring press attention and remind people to get out and support Saxby."
Palin stumped with Chambliss at four events on Monday. More than 3,000 attended each of the events, according to press reports.
The Democrats sent their heavy-hitters to Georgia on behalf of their candidate as well. Former President Bill Clinton and former Vice President Al Gore both campaigned with Martin and President-elect Obama recorded automated phone calls to encourage people to vote for the Democratic candidate.