Mitt Romney's showing at Wednesday night's debate paid off, according to a Saturday tweet from his campaign spokeswoman.

In the 48 hours post-debate, Romney's campaign raised "more than $12 million," press secretary Andrea Saul tweeted.

Two-thirds of those who watched the debate between the GOP presidential nominee and President Barack Obama said Romney won the debate, a CNN/ORC International poll conducted on the night of the event found. One in four said the night went to Obama.

The debate also led to an increase in supporters volunteering with the campaign, Saul wrote. The night of the debate, there were "more than 2 donations/second."

A major super PAC supporting Romney's candidacy had a strong night, too, the group's founder said on Thursday.

"I think that today will probably be the best fund-raising day we've had, if not one of the top two fundraising days we've ever had," Charlie Spies of Restore our Future said on CNN's "Erin Burnett OutFront."

Obama's campaign has not said how much it raised post-debate, but it did announce Saturday that it set a fundraising record in September, bringing in $181 million.