Mitt Romney claimed six Super Tuesday victories, including a very narrow win in Ohio, the most closely watched of the 10 states holding contests.
Romney also scored a home state win in Massachusetts to go with primary victories in Vermont and in Virginia. He also added the Alaska and Idaho caucuses to his column.
Rick Santorum won in Tennessee, Oklahoma, and North Dakota.
"There wasn't a single state in the list I just gave you where I spent more money than the people I was able to defeat to win that state," Santorum said. "In every case, we overcame the odds."
Romney says as the days go by, it is only getting better for his campaign.
"We're doing some counting," Romney said. "We're counting up the delegates and it looks good. And we're counting down the days to November and that looks even better."
Exit polling shows Romney was propelled by moderate and secular voters in Ohio's primary.
Santorum drew strong support from the state's conservatives and eked out a modest lead among blue collar voters.
Gingrich Wins Georgia
In the meantime, Newt Gingrich scored another win in his roller coaster campaign.
Gingrich won easily in Georgia, his home state. He says the victory defies the establishment and says he will stage another comeback with 'the power of ideas.'
"You just can't quite get across to them it's alright. There are lots of bunny rabbits that run through; I am the tortoise. I just take one step at a time," said Gingrich.
Gingrich will campaign Wednesday in Alabama and Mississippi.