WASHINGTON, D.C. -- Mitt Romney may be the Republican frontrunner, but all eyes were on Rick Santorum for Tuesday's three contests in the GOP nomination race.

Early voting results from the Minnesota caucuses and Missouri's non-binding primary Tuesday night showed Santorum beating Romney in both states.

Colorado also held caucuses Tuesday and Romney was poised to win there, but results were expected later Tuesday.

Following Newt Gingrich's big win in South Carolina, the Republican nomination race had been seen by many as a two-horse race between him and Romney.

But Santorum's wins Tuesday could reshape this race and make the former Pennsylvania senator relevant again.

Earlier Tuesday in Colorado, he asked voters to "reset the race."

Santorum had failed to gain any traction, despite having won a 34-vote squeaker in the Hawkeye State last month.

Since Iowa, he's finished third or fourth in every contest and had been all but written off.

But his string of poor showings that have left him on the sidelines for the brutal war raging between Gingrich and Romney may actually have worked to Santorum¹s advantage. His favourability ratings hovered around 70% ahead of Tuesday's contests in Minnesota, Colorado and Missouri, while Gingrich and Romney had favourability ratings around 40%.

And a new Public Policy Polling survey showed Santorum besting Romney in both Missouri and Minnesota by 13 and 9 points respectively.

While Romney is expected to win Colorado, a state he carried in 2008 and where he is currently polling 10 points ahead, his campaign was busy Tuesday lowering expectations for Minnesota and Missouri.

"Mitt Romney is not going to win every contest," said Romney advisor Rich Beeson in a public memo to reporters. "John McCain lost 19 states in 2008, and we expect our opponents will notch a few wins, too."

Santorum, though, raised the bar for himself in Colorado, saying he expects to outperform the current polls there.

"I am actually encouraged we're going to do better here than some of the polls have suggested, I mean the polls have us pretty far down here," Santorum said at a rally in Denver Monday night. "I'm not too sure we can win here, but I think we'll come closer than the polls suggest."

Even Gingrich, who has more or less conceded contests this month and is focussed instead on a series of contests taking place on March 6 -- known as 'Super Tuesday' when 10 states hold primary votes -- predicted his rival would have a good night.

"I think Santorum's going to have a pretty good day tomorrow (Tuesday), and he will have earned it," Gingrich said Monday night, calling Santorum a "friend."

Regardless of how the votes break down, all three contests Tuesday are essentially beauty contests like Iowa, with no delegates being awarded from any of them.

State conventions for Colorado and Minnesota and a proper caucus in Missouri later this spring will officially divvy up the more than 100 delegates at play in the three states.

The eventual nominee will need 1,144 delegates to secure the Republican nomination. Currently Romney leads in delegates with 101. Gingrich has 32 delegates to date, Santorum has 17, and libertarian-leaning Ron Paul has nine.

On Saturday, the week-long Maine caucuses wrap up and Michigan and Arizona hold their primaries on Feb. 28. Romney is favoured to win all three.

More than 400 delegates will be awarded on Super Tuesday.