Mitt Romney’s performance in Monday’s debate turned out to be a game-changer after all.  Three days after a Rasmussen poll of likely Republican primary voters showed Newt Gingrich up by nine points, a new survey taken yesterday shows Romney has an eight-point lead heading into tonight’s CNN debate:

Mitt Romney has jumped back ahead in the fevered Florida Republican Primary race with his support back to where it was before Newt Gingrich’s big win Saturday in South Carolina.

The latest Rasmussen Reports telephone survey of Likely Florida Republican Primary Voters, taken Wednesday night, shows Romney with 39% support to Gingrich’s 31%. Former U.S. Senator Rick Santorum earns 12%, and Texas Congressman Ron Paul runs last with nine percent (9%). Four percent (4%) prefer some other candidate, and seven percent (7%) are undecided.

That’s a ten-point drop for Gingrich since Sunday’s survey, and a seven-point gain for Romney.  The momentum of the debate performance, and perhaps the renewed aggression on the campaign trail for Romney, seems to be firmly established in new polling.  That makes tonight a must-win evening for Gingricg, and that probably means a lot of bloody knuckles for both men.

Let’s take a look at the differences in the internals.  Very conservative voters still choose Gingrich as the stronger candidate against Obama, but that’s down to 47/34 from 56/24 in the earlier survey.  Women had given a three-point edge to Romney on this question, but that has now jumped to 22 points, 52/30, and men now give Romney a nine-point lead where Gingrich had a double-digit advantage.  The overall rating on this question now favors Romney by 15 points, 49/34, where Gingrich led by 3 on Sunday.  Gingrich’s favorability didn’t change much at 63/35, but Romney’s increased to 73/25.

This looks like a very volatile race, though.  A big debate stumble by Romney could reverse this yet again.  However, with the tax issue off the table and every other line of attack likely to be a rerun, there’s a question about whether Gingrich can find another way to knock Romney off his stride as he did in South Carolina, or go after the media like he did to win in two debates there.