The two trailing contenders in the recent Florida primary and Nevada caucuses said Sunday they would stay in the GOP presidential race and criticized front-runner Mitt Romney and main challenger Newt Gingrich as flawed candidates.

Former Pennsylvania Sen. Rick Santorum, who finished fourth in Nevada on Saturday, lambasted Romney as a "uni-dimensional candidate." Both Santorum and third-place finisher Ron Paul justified their continued candidacies because Romney, in Paul's words, "doesn't satisfy a lot of people."

Santorum argued that Romney's candidacy would be undermined if the economy continued to improve. Job figures released Friday showed unemployment dropping to 8.3%, its lowest level since 2009.

"I mean, all he talks about is being the CEO, being the CEO, being the businessman," Santorum said of Romney on "Fox News Sunday." "First of all, I'm not sure that's the greatest qualifications for being president of the United States. But if it is, the qualification (by Romney) is that 'I'm someone who can run the economy, even though I don't believe the president runs the economy.' "

The presidency, Santorum said, is "not necessarily a CEO type of position, and secondly, Gov. Romney - even more than Speaker Gingrich - doesn't create the contrast that we need to beat (President) Barack Obama."

In particular, Santorum repeated his campaign assertion that both Romney and Gingrich are too similar to the president on major issues such as health care reform, climate change and Wall Street bailouts, while his record is the only one representing true conservative principles that contrast with Obama's policies and record.

Paul, the Texas congressman, is looking to caucus states such as Nevada to amass the delegates he needs to be a player at the Republican convention in Tampa, Florida in August. He said Sunday that he hopes to win the GOP nomination but remains realistic.

"Well, the first thing you want to achieve is get as many votes as you can and get as many delegates and set your target high," Paul said on ABC's "This Week with George Stephanopoulos." "And, of course, you set it for victory, but you have to live within the real world."

As of Sunday morning, Romney had 48% of the Nevada count to 23% for Gingrich, 18% for Paul and 11% for Santorum. In 2008, Paul finished second to Romney in the Nevada caucuses with 14% support.

"If you go from second to third, there would be disappointment, but also on the positive side, we will get a bloc of votes. We will still get some delegates," Paul noted. "And we still will pursue, you know, our plan to go into the caucus states. And we'll have to wait and see how things go."

Paul also got in a dig at Romney when asked if he might be able to bring around the front-runner to some of his libertarian positions on key issues as the nomination process proceeds.

"Yeah, I think Mitt could change his mind. He's changed his mind in the past," Paul said, referring to Romney's shift to more conservative stances since his years as Massachusetts governor. "If he hears from our young people and voters and we continue this, yeah, he's going to change his mind, if there's a political benefit to it."

However, Paul said he was not concerned about the harsh negative turn of the campaign, particularly between Romney and Gingrich, as well as ads produced by his own campaign. Some Republicans fear the bitter attacks could harm the eventual candidate for the general election race against President Barack Obama later this year.

"I don't worry about that," Paul said on the ABC program. "I worry about myself. I worry about the message. I worry about the country. I worry about the wars going on. I worry about the economy in the real sense of what it's like to have runaway inflation. Those are things that I worry about, and that's what energizes my supporters, and that's why we get these thousands of people coming out."

The next events on the campaign trail are Tuesday, with caucuses in Colorado and Minnesota, as well as a non-binding primary in Missouri. Asked if it would be a make-or-break day for his campaign, Santorum said on Fox: "Oh no, not at all."

"I think we're going to show improvement," Santorum said, noting the five contests so far in Iowa, New Hampshire, South Carolina, Florida and Nevada were the first five in 2008 also, when both Romney and Paul also waged campaigns.

Romney and Paul "had an advantage because they had spent a lot of time and money not just in this year's campaign but for the last four years in working on those states," Santorum said.

"Now we're getting to the states where people don't have the natural advantage, don't have the time commitment, the staff commitment to really build an organization like they did in these first five," Santorum continued. "I think we're going to do very well here in Minnesota. I think we're going to do very well in Colorado and we've got a one-on-one matchup against Mitt Romney in Missouri" because fellow conservative Gingrich failed to get his name on the ballot there.