Rubio touted his international affairs record on the Senate Foreign Relations Committee, while taking aim at the experience of Ohio Governor John Kasich, former Florida Governor Jeb Bush and the GOP frontrunner, Donald Trump -- all of whom won more votes than him in Tuesday's New Hampshire primary.
"We'll have a debate on Saturday. Who on that stage has more experience or has shown better judgment or a better understanding of the foreign policy and national security issues than I have, on that stage?" Rubio asked at a town hall on Hilton Head Island.
"Because the governors haven't dealt with foreign policy, in the case of John Kasich in a long time."
The Ohio governor -- and former congressman -- on Wednesday defended his foreign policy experience at an appearance in South Carolina, citing his long tenure on the House Armed Services Committee.
"I served on the defense committee for 18 years," Kasich said. "I was there during the Reagan build up, when the Berlin Wall came down, and when Saddam (Hussein) was pushed out of Kuwait."
Rubio also targeted former Florida Governor Jeb Bush's foreign policy credentials.
"Jeb Bush has no foreign policy experience, and I respect his family," Rubio said. "I thank god every day that George W. Bush was President, but Jeb has no foreign policy experience."
Bush responded to Rubio's claims in an interview with the Washington Post.
"Let me ask you, what has (Rubio) accomplished? What has he done in his life that makes you think he can make the tough calls, develop strategy? . . . Maybe he can, but I don't know," Bush said.
The Florida senator went on to jab Trump, as well.
"Donald Trump has zero foreign policy experience," Rubio said. "Negotiating a hotel deal in another country is not foreign policy experience."
Trump, Kasich, and Bush beat Rubio in New Hampshire, with the mogul on top, the Ohio governor second and his fellow Floridian in fourth. Polls show Rubio trailing Trump and Ted Cruz in South Carolina.