Shrugging off a consensus among political analysts, focus group participants and snap polls that Romney -- the Republican nominee and former Massachusetts governor -- had the better debate performance, Obama suggested Romney gave a dishonest accounting of his plan for tax reform.
Obama got a laugh when he told the crowd when he walked onstage Wednesday he "met this very spirited fellow who claimed to be Mitt Romney."
"But it couldn't have been Mitt Romney -- because the real Mitt Romney has been running around the country for the last year promising $5 trillion in tax cuts that favor the wealthy. The fellow on stage last night said he didn't know anything about that," the president said.
"The real Mitt Romney said we don't need any more teachers in our classrooms. But the fellow on stage last night, he loves teachers -- can't get enough of them. The Mitt Romney we all know invested in companies that were called 'pioneers' of outsourcing jobs to other countries. But the guy on stage last night, he said that he doesn't even know that there are such laws that encourage outsourcing -- he's never heard of them. Never heard of them. Never heard of tax breaks for companies that ship jobs overseas. He said that if it's true, he must need a new accountant.
"Now, we know for sure it was not the real Mitt Romney, because he seems to be doing just fine with his current accountant."
Obama said Romney "does not want to be held accountable for the real Mitt Romney's decisions and what he's been saying for the last year."
"And that's because he knows full well that we don't want what he's been selling for the last year," the president said. "So Governor Romney may dance around his positions, but if you want to be president, you owe the American people the truth."
Obama repeated his assertion that Romney's tax proposal would require either "blowing up the deficit or sticking it to the middle class."
"That's the math," he said. "We can't afford to go down that road again."
Obama reiterated the same points at a later rally at the University of Wisconsin in Madison, saying, "We can't afford to roll back regulations on Wall Street banks or oil companies or insurance companies. ... It is not change, it is a relapse, and we're not going to do it."
During his appearance in Madison, Obama ridiculed Romney for saying he would address deficit spending by cutting out funding for public television.
"But I just want to make sure I got this straight," he said. "He'll get rid of regulations on Wall Street, but he's going to crack down on Sesame Street. Thank goodness somebody is finally cracking down on Big Bird. Who knew that he was responsible for all these deficits? Elmo has got to watch out."
The campaign rally in Denver came as the Gallup Daily tracking poll showed Obama with a 49-45 lead over Romney and a job approval rating of 54 percent, his highest approval rating since November 2009.
Notable deaths of 2014 [PHOTOS]