Des Moines, Iowa (CNN) -- Rick Santorum started the new year riding the wave of a strong finish in the last major poll before Tuesday's Iowa caucuses and looked to rally his supporters in a series of events on Sunday.
There were few surprises in Saturday night's Des Moines Register poll -- front-runners Mitt Romney and Ron Paul finished 1-2 as they had in other polls during the week. But the Register poll showed Santorum, who just weeks ago had registered only in single digits, pulling ahead of rivals Newt Gingrich and Rick Perry.
The Register also pointed out that if only the last two days of the four-day poll were considered, Santorum would be ahead of Paul in second place.
Santorum's rise is the latest in a campaign-long series of votes testing conservative candidates against Romney, who is favored by establishment Republicans and has finished at the top or in the top tier in most polls since he announced his candidacy in June.
Santorum says he knew his turn would come.
"People have asked me, 'When are you going to get your surge? You're not going anywhere. Your message must not be resonating,'" the former Pennsylvania senator said Sunday on NBC's "Meet the Press."
"I said my surge is going to come on January 3rd after the people of Iowa do what they do, which is actually analyze the candidates, figure out where their positions are, find out who's the right leader, who's got what it takes to defeat Barack Obama and to lead this country, and I've always relied that when that crunch time comes, in these last two weeks, that's when we were going to start to pick up, and that's exactly what happened," he said.
While Santorum is benefiting from the buzz of the poll results, another figure speaks to the prolonged test drive of conservative anti-Romney candidates -- 41% of those surveyed in the Register poll say they could still change their minds about their choice.
The fact that Iowans were still undecided didn't surprise one of the state's top Republicans, Rep. Steve King, but, "I am a little surprised that that number seems to be going up, if I'm seeing the same polls, instead of down, creeping up. And I'm going to make this point, too, that encourage your people everywhere, especially, and to come out to the caucus. Going there undecided is just fine. You'll be in good company with lots of Iowans going to the caucuses undecided," he said on CNN's "State of the Union" with Candy Crowley.
King told Crowley that he, too, wasn't yet decided on a choice, which is a much-coveted endorsement in Iowa.
"If that instant comes that I'm convinced that one will do a significant better job than another, I won't hesitate, I'll step in," King said. "But it has to be a conviction on my part. I don't think I'd be doing justice to this privilege that I have if it were not a conviction."
The Register poll showed Romney with 24% and Paul at 22%. Santorum was at 15%, former House Speaker Newt Gingrich stood at 12% and Texas Gov. Rick Perry was at 11%.
Minnesota Rep. Michele Bachmann was at 7% and former Utah governor and ambassador to China Jon Huntsman isn't competing in the state, instead concentrating on New Hampshire, which votes a week later.
In his NBC interview, Santorum characterized the GOP race as three primaries -- Romney and Gingrich competing for the establishment Republican vote, Paul leading the libertarian GOP race and a conservative primary between Bachmann, Perry and himself.
"And our feeling from the very beginning, if we can pace ahead of Perry and/or Bachmann, that we'd be in good shape, and you know, we're moving in that direction certainly right now," he said.
The strong showing in the Register poll seems to have had an effect on Santorum's Sunday events — the candidate had three "rallies," as his campaign characterized them, as opposed to the small "town halls" and "meet and greets" that the campaign routinely announces.
As Santorum has passed him in polls, Perry, once a front-runner before a series of stumbles sent his poll numbers plummeting, has steadily criticized Santorum's record on spending votes when he was in the Senate as he's tried to draw contrasts between himself and Santorum. He continued those attacks Sunday.
"Well, there are a lot of differences between myself and Rick Santorum, as Michele (Bachmann) talked about he's got a spending problem, he's got an earmark problem," Perry said on "Fox News Sunday." "I'm going to let him explain to people, why did you vote to raise the debt ceiling, vote for the 'Bridge to Nowhere,' Montana sheep institute?" Perry said, referring to highly publicized examples of legislators' pet projects buried in appropriations bills. "You're telling us you're a fiscal conservative?"
Santorum has defended his record, saying that such horse-trading was how Congress did business when he was in the Senate and that he supported subsequent reform efforts after he left Washington.
Meanwhile Sunday, front-runner Romney picked up the endorsement of another of Iowa's larger newspapers when the Quad City Times backed his candidacy.
The paper praised him as an "articulate, polished chief executive with a range of business and governing experience that far exceeds his rivals."
The Des Moines Register and Sioux City Journal had earlier endorsed Romney.
The former Massachusetts governor was scheduled to meet voters to discuss jobs and the economy later Sunday in Atlantic before holding a rally Sunday evening in Council Bluffs.
Paul was spending the New Year's weekend back home with his wife in Texas before returning to Iowa on Monday.
In an interview with Crowley on "State of the Union," the three-time presidential candidate predicted he would finish first or second in Iowa but Tuesday's outcome wouldn't affect the momentum he has gained in recent weeks, rising to rival Romney in most polls.
"I would say the people are with me on this, and the momentum is going to continue regardless of what happens and what place I am Tuesday night," Paul said.
With Paul's rise to the top tier, rivals have attacked his non-interventionist views on foreign policy and less aggressive stance on Iran's nuclear program. They've also resurrected newsletters published under Paul's name in the 1990s that included racist comments. Paul has said he was unaware of the content of the newsletters at the time and rejected the content.
In his Sunday interview, Paul drew contrasts between his consistent positions on the issues and said rivals are desperate to find ways to attack him.
"They've been all over the place. They've been flip-flopping and they can't defend themselves," he said. "They're having a little trouble finding any flip-flops on me, so they have to go and dig up and distort and demagogue issues."
As to assertions that he would be unelectable in the general election, Paul countered, "I've been electable. I was elected 12 times once people got to know me in my own congressional district. So I think that might be more propaganda than anything else."
Also Sunday, Bachmann played off her last-place finish among active candidates in Iowa, saying on ABC's "This Week" that the crowds she has seen at recent events "isn't yet reflected in the polls."
The Minnesota congresswoman said the nature of the caucuses are unpredictable but she did predict a "miracle" Tuesday.
"People gather in living rooms, they gather in elementary schools and churches, and they make their decision on the spot with their neighbors," she said.
When asked if a last-place finish would knock her out of the race, Bachmann said she not only plans to compete in the upcoming New Hampshire, South Carolina and Florida primaries but "to go all the way."
"We've bought tickets to head off to South Carolina, and we are looking forward to the debates," she said. "January is a very full month. We're here for the long race. This is a 50-state race."
CNN's John Helton, Josh Levs and Paul Steinhauser contributed to this report.