Clinton figured most during the last primary debate in Des Moines -- just days ahead of the Iowa Caucus on February 1.
From Marco Rubio to Jeb Bush to Chris Christie, everyone claimed they were positioned most suitably to defeat Clinton.
"I know that if Iowa helps make me the Republican nominee, I will defeat Hillary Clinton. Hillary doesn't want to run against me, but I cannot wait to run against her. And, I cannot wait to earn the opportunity to do it because she cannot be the president of the United States," Rubio said.
"I've seen polls where I'm beating Hillary Clinton pretty regularly... I'm confident if I win this nomination, I will aggressively go against her and beat her. I'm running hard and I believe I'll be the Republican nominee and I'll be the one best suited to beat Hillary Clinton, who should not be president of the United States," Bush claimed.
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Christie, too, weighed into the chorus.
"There is no one on this stage better prepared to prosecute the case against Hillary Clinton than I am. I will be ready. I will take her on, and when I take her on I guarantee you one thing, she will never get within 10 miles of the White House. The days for the Clintons in public housing are over," said the New Jersey governor.
"I do think that her position as promoting women's rights and fairness to women in the workplace, that if what Bill Clinton did any CEO in our country did with an intern, with a 22-year- old, 21-year-old intern in their office, they would be fired. They would never be hired again," Paul said.
"And the thing is, she can't be a champion of women's rights at the same time she's got this that is always lurking out there, this type of behaviour. So it is difficult."
In his closing argument, Bush said the US desperately needed a conservative leader as the president.
Clinton, who served as the Secretary of State in the first term of President Barack Obama, has been leading the Democratic nomination polls against her nearest rival Vermont Senator Bernie Sanders.