Mitt Romney edged out Rick Santorum to win the Ohio Republican primary by a percentage point in the most-watched state of the 10 that voted on Super Tuesday.

Romney, a former Massachusetts governor, trailed Santorum, a former U.S. senator from Pennsylvania, for most of the night, but came from behind in tallying early Wednesday to win by an estimated 10,000 votes out of 1.2 million cast, 38 percent to Santorum's 37 percent.

No Republican has ever won the presidency without winning Ohio.

Former U.S. House Speaker Newt Gingrich got 14.6 percent of Ohio's GOP primary vote while U.S. Rep. Ron Paul of Texas got 9.3 percent. Other candidates got the vote's remaining 1.2 percent.

Romney's victory gave him five wins Tuesday -- Ohio, Virginia, Vermont, Massachusetts and Idaho. He won Virginia in a two-man race against Paul since Gingrich and Santorum failed to qualify to be on the ballot.

Paul garnered 40 percent of the Virginia vote.

Santorum won in Tennessee, Oklahoma and North Dakota. Gingrich won Georgia.

Romney held a narrow lead over Santorum as votes from Alaska's Republican presidential preference poll were counted Tuesday night. With 68 percent of precincts reporting, Romney led with 33 percent to Santorum's 30 percent.

Ohio emerged as Tuesday's biggest trophy because of the significance Republicans give it in their general election fight against President Barack Obama, The Wall Street Journal reported.

It was also seen as an industrial-state matchup similar to that in last week's Michigan primary, where Romney edged Santorum after trailing him in the state for weeks.

Before the Ohio vote was final, Romney told supporters in Boston, "I'm going to get this nomination."

But he said his campaign was "counting up delegates" and acknowledged he made mistakes in recent weeks.

"I've listened and I've learned," he said. "I hope I'm a better candidate for it."

Santorum told a crowd in Steubenville, Ohio: "We've won the West, the Midwest and the South, and we're ready to win across this country."

He also took a swipe at Romney.

"I've never passed a statewide government-run healthcare system. Gov. Romney did," he said.

Gingrich spoke from his election night headquarters in Atlanta, where supporters chanted, "Newt, Newt, Newt, Newt."

"I hope the analysts in Washington and New York who spent June and July explaining our campaign was dead will watch this tonight and learn a little bit from this crowd and from this place," he said.

Gingrich said he was now pinning his hopes, in part, on primary victories in Mississippi and Alabama next week.

Paul told about 500 people in Fargo, N.D., that no matter what the final vote count, "We always win!"

He attacked the two-party system as two sides of the same coin.

"You elect one party to cut the spending -- they raise the debt and the spending as well," he said. "Another party is supposed to do the job -- they go in and nothing changes.

"So if you look at the candidates today, there is very little difference -- except for one," he said.

The 10 Super Tuesday states will allot 437 convention delegates, or more than a third of the 1,144 needed to win the GOP nomination in August.

The next contest comes Saturday, when Kansas Republicans hold caucuses, followed by Alabama and Mississippi primaries Tuesday.