DES MOINES, Iowa - (AP) - Mitt Romney eked out a minuscule 8-vote victory over Rick Santorum in Iowa's Republican presidential caucuses, the state party chairman said early Wednesday, ringing down the curtain on an improbable first act in the campaign to pick a challenger to President Barack Obama in the fall. Appearing hours after the caucuses had ended, Matt Strawn said Romney had 30,015 votes, to 30,007 for Santorum, whose late surge carried him to a near win. "Game on," declared Santorum, jaw set, after easily outdistancing several other contenders to emerge as Romney's unvarnished conservative rival for the primaries yet ahead. Romney looked past his GOP rivals and took aim at Obama. "The gap between his promises four years ago and his performance is as great as anything I've ever seen in my life," he told supporters in Iowa's capital city. The narrow margin, out of more than 122,000 straw poll ballots cast, was a fitting conclusion to a race as jumbled as any since Iowa gained the lead-off position in presidential campaigns four decades ago. Texas Rep. Ron Paul ran third and former House Speaker Newt Gingrich was fourth. Both men vowed to carry the fight to New Hampshire's primary next week and beyond. Not so Texas Gov. Rick Perry, who came in fifth and told supporters he would return home to reassess his candidacy. Minnesota Rep. Michele Bachmann was a distant sixth, and her campaign appeared in disarray. She told reporters she would carry on - less than an hour after her campaign manager raised doubts in an Associated Press interview about whether she would stay in the race. Romney is heavily favored in New Hampshire's first-in-the-nation primary on Jan. 10. South Carolina on Jan. 21 figures to be a tougher test, the first contest in the South and a state that is part of the Republican political base.