With Mitt Romney hoping to get that elusive win in the Deep South and Newt Gingrich desperately needing another Southern victory to keep his presidential hopes alive, Rick Santorum had one message Tuesday night:

"We did it again."

That's how Santorum begin his victory speech after being declared the winner of the Alabama Republican presidential primary. Just minutes after his rally ended, Santorum also was declared the winner in Mississippi, giving the former senator from Pennsylvania a Southern sweep Tuesday.

Santorum won despite being outspent heavily (again) by Romney. It gave him momentum in a GOP race that continues to show no sign of coming to an end.

Since Santorum failed to get at least 50 percent of the vote in either state, the states' delegates will be awarded proportionally among the candidates. And with Romney's wins in the Hawaii and American Samoa caucuses late Tuesday, he offset any delegate gains Santorum had from the two Southern primaries. According to the Associated Press, Romney added at least 41 delegates and Santorum won at least 35 Tuesday. Gingrich got at least 24 delegates and Ron Paul got at least 1. Nine delegates were still to be determined.

But the night was still a disappointing one for Romney. The former Massachusetts governor finished third in both states. He can't seem to pull away even though he wields sizeable advantages in both money and organization, and even though he enjoys the backing of many Republican leaders.

The contests in Alabama and Mississippi brought out some of the highest percentages of self-identified evangelical voters so far this primary season. According to CNN exit polls, 80 percent of Mississippi voters and 75 percent of Alabama voters on Tuesday described themselves as evangelicals. Santorum won support from 35 percent of those voters in both states, besting Gingrich and Romney.

Santorum, appearing Tuesday night at a rally in Lafayette, La. (Louisiana's primary in on March 24), acknowledged those evangelical voters early in his victory speech.

"The most common thing I hear from people … is people come up and say I'm praying for you," Santorum said. "I just want to thank you for that, and I want to thank God for giving us the strength every day to go out there and to be clear in our message and our vision for this country."

Santorum later named "integrity of the family and the centrality of faith in our lives" as two of the key themes for his campaign.

It is a campaign that is becoming a war of attrition between Santorum and Romney. Santorum continues to exceed expectations because more average Republican voters continue to balk at the party establishment's efforts to anoint Romney. Mississippi Gov. Phil Bryant endorsed Romney ahead of the primary while Alabama Gov. Robert Bentley publicly stated that Romney had the best chance to win the nomination.

"This is a grassroots campaign for president," Santorum explained. "This campaign is about ordinary folks doing extraordinary things … sort of like America."

But in order for Santorum to keep defying the odds, he likely needs Gingrich to exit the race. In the days leading up to Tuesday's primaries, some speculated that Gingrich would no longer be a viable candidate if he did not win at least one of the two states. But after finishing second in both Alabama and Mississippi, Gingrich vowed to carry his campaign all the way to the Republican National Convention in Tampa this August.

"The elite media's effort to convince the nation that Mitt Romney is inevitable just collapsed," Gingrich said Tuesday night. "If you are the frontrunner, and you keep coming in third, you are not much of a frontrunner."

Gingrich may have taken jabs at Romney on Tuesday night, but his continued presence in the race primarily siphons away delegates from Santorum, making it harder for Santorum to gain ground on Romney's delegate lead.

Santorum vowed to continue campaigning everywhere there are delegates. He was scheduled to get on a plane early Wednesday morning and head to Puerto Rico, whose 23 delegates are on the line next week.

Meanwhile, Romney has begun to pour his sizeable resources into Illinois, which holds a primary for its 69 delegates next Tuesday. Romney's campaign and the Super PACs backing him are spending a combined $2.26 million on television ads in Illinois.

Appearing before nearly 500 people in Liberty, Mo., on Tuesday, Romney all but ignored both Tuesday's Deep South primaries and his GOP rivals.

"I'm the one guy in this race who can beat Barack Obama," he said from Missouri, which holds its formal caucus on Saturday. "The president has failed. He's not a bad guy. He's just over his head."