In campaign appearances after the debate, Obama said the Romney he met on the stage on Wednesday night was not the same Romney he knew.
"When I got on the stage, I met this very spirited fellow who claimed to be Mitt Romney. But I know it couldn't have been Mitt Romney -- because the real Mitt Romney has been running around the country for the last year promising US $ 5 trillion in tax cuts that favour the wealthy," he said.
"Yet, the fellow on the stage last night -- who looked like Mitt Romney -- said he did not know anything about that. It was all news to him. The real Mitt Romney said that we don't need any more teachers in the classroom.
"But the fellow on stage last night, he said he loves teachers -- can't get enough of them," he said.
He accused Romney of being dishonest on a host of policy issues and accused him of glossing over details of his economic plan.
The US president also hit at Romney for saying on stage that he hadn't heard of tax breaks for companies that outsource jobs, despite being known as a "pioneer" of companies that have outsourced in the past.
"And he said, if that's true, he must need a new accountant. So now we know for sure that wasn't the real Mitt Romney, because the real Mitt Romney is doing just fine with the accountant that he already has," Obama said, referring to the first of the three presidential debates he had with Romney a day earlier.
"Whoever it was that was on stage last night doesn't want to be held accountable for what the real Mitt Romney has been saying for the last year, and that's because he knows full well that we don't want what he's been selling over the last year.
"Governor Romney may dance around his positions, he may do a tap dance and a two-step, but if you want to be president, then you owe the American people the truth," Obama said.
"So here's the truth. Governor Romney cannot pay for his US $ 5 trillion tax plan without blowing up the deficit or sticking it to the middle class. We can't afford to go down that road again."
The Obama campaign too slammed Romney.
"The problem with it was, that none of it was rooted in fact. Much of it was rooted in deception. From his very first answer, when he tried to disown his US $ 5 trillion tax
programme, which would skew to the wealthy, and for which he has no way to pay, as was apparent last night," said David Axelrod, senior advisor to the president in a conference call.
"To issues like Medicare, where he knowingly and willfully tried to deceive senior citizens about what the impact of his plan would be," Axelrod said.
In response, the Romney campaign said that by making such statements, the Obama campaign has gone into a damage control exercise.
"The Obama campaign's conference call today was just like the president's performance last night. The campaign, like the president, offered no defence of the president's first term record or vision for a second term, and instead, offered nothing but false attacks, petulant statements, and lies about Governor Romney's record," said Amanda Henneberg, the Romney campaign spokesperson.
Meanwhile, the Obama campaign has said it would make adjustments in its election strategy given the impressive performance of Romney.
"Moving forward, you know we're going take a hard look at this, and we're going to have to make some judgements as to where to draw the lines in these debates, and how to use our time," Axelrod said.
"In terms of changes and such, these things are always -- it's like a playoffs in sports. You evaluate after every contest and you make adjustments. And I'm sure that we will make adjustments. I don't see us adding huge amounts of additional prep time. I think there are some strategic changes that have to be made, and we'll make them," Axelrod said.
News reports that Obama will look to be more aggressive in the next debate which has been scheduled for October 16 in Hofstra, New York.
Image: US Republican presidential nominee Mitt Romney speaks as President Barack Obama listens during the first presidential debate in Denver | Photograph: Jim Bourg/Reuters