Republican presidential candidate Mitt Romney headed back onto the campaign trail on Wednesday hoping to re-energize his campaign after narrowly avoiding a humiliating defeat by rival Rick Santorum in his home state.

Romney scored an all-important victory over Santorum in Michigan's Republican presidential primary on Tuesday, but his margin of victory was only 3 percentage points in the state where he grew up and where his father was governor in the 1960s.

The former Massachusetts governor also rolled to an easy victory in Arizona's primary, but all eyes had been on Michigan, where Santorum, a former Pennsylvania senator known for unflinching religious conservatism, had posed an unexpectedly stiff challenge.

We didn't win by a lot, but we won by enough and that's all that counts, Romney told cheering supporters on Tuesday night.

The results were enough to ease the worst concerns about Romney's ability to win over the conservative Republican base and reinforce his claim to be front-runner in the race for the nomination to oppose Democratic President Barack Obama in the November 6 general election.

But the narrow margin in his home state left Romney under intense pressure going into Super Tuesday next week, when 10 states across the country hold presidential nominating contests.

A month ago, they didn't know who we are. They do now, Santorum told supporters on Tuesday night.

Romney headed to Ohio, one of the most important Super Tuesday states, on Wednesday for a mid-morning rally in Toledo and an afternoon town hall meeting in Bexley.

Santorum headed to Tennessee, which also votes next Tuesday, for afternoon rallies in Powell and Knoxville.

Romney is a former private equity executive who has stressed that his combination of experience in government and private business makes him the best candidate to lead a country still grappling with the aftermath of a recession.

Aides said he planned to pound on that message as he campaigned. Romney, who has a personal fortune of some $250 million, has struggled to connect with blue-collar voters. And his centrist record as governor of Massachusetts six years ago worries some conservatives.

We're going to win some, we're going to lose some. But this is a campaign built to go the distance and has the structure and organization to not only win the nomination but beat President Obama in November, a Romney aide said.

APPEALING TO BLUE-COLLAR VOTERS

Santorum has risen in polls by appealing to the religious right and sending a populist economic message tied to his working-class roots as the grandson of a coal miner. He has led in nationwide opinion polls since winning state contests in Missouri, Minnesota and Colorado on February 7.

With the rise of Santorum, best known for his unflinching social positions such as opposition to abortion rights and gay marriage, the Republican primary fight had become increasingly focused on divisive social issues.

Both candidates have worked to refocus their message on the U.S. economy, which had been expected to be the central issue in the 2012 election.

Romney won 41.1 percent of the votes in Michigan. Santorum took 37.9 percent, Texas congressman Ron Paul had 11.6 percent and former Speaker of the House of Representatives Newt Gingrich garnered 6.5 percent.

In Arizona, Romney won 47.3 percent to 26.6 percent for Santorum, 16.2 percent for Gingrich and 8.4 percent for Paul.

Santorum had appealed to Democrats in Michigan to back him in the primary, which was open to voters of all parties - a tactic that Romney denounced as dirty tricks.

Exit polls showed that Democrats made up about 9 percent of those voting, roughly in line with primaries in earlier years. Santorum carried 53 percent of those voters.