A poll of debate viewers by CNN showed 54 per cent believed Obama had outperformed his rival, while 30 per cent favoured McCain.
Two snap polls, one by CBS, the US newsbroadcaster, also judged Obama the winner of the debate on Tuesday night at Nashville, Tennessee's Belmont University.
The polls indicated voters favour Obama on economic issues, which have taken centre stage amid the global financial turmoil.
Mortgage plan
With the debate behind them, the rivals refocused their energy on the campaign trail on Wednesday.
McCain, seeking to reverse his rival's momentum, unveiled a $300bn plan to aid homeowners suffering under the global credit crunch that began last year over unpaid sub-prime mortgages.
"Under my orders as president, the secretary of the [US] Treasury will carry out a home-ownership resurgence plan," McCain said at a rally in Bethlehem, Pennsylvania.
|
"The dream of owning a home should not be crushed under the weight of bad mortgages"
John McCain, Republican party presidential candidate
|
"The dream of owning a home should not be crushed under the weight of bad mortgages."
Calling the proposal a "critical first step", he said the government would buy troubled loans from homeowners and restructure them into more affordable mortgages.
Obama's campaign dismissed the ideas as "more costly and out-of-touch than we ever imagined".
Jason Furman, policy director for the Obama campaign, said: "John McCain wants the government to massively overpay for mortgages in a plan that would guarantee taxpayers lose money, and put them at risk of losing even more if home values don't recover."
The US congress has already given the treasury the authority to spend around $700bn in taxpayer funds to buy bad mortgage debt from any financial institution over the next two years.
Obama told supporters at an outdoor rally in Indianapolis that McCain was offering the same strategies "that led us into this mess in the first place".
"This is a time for resolve and steady leadership," he said.
'Hussein' invoked
With pressure building on McCain as he lags in the polls, supporters again invoked Obama's middle name, Hussein, in an apparent attempt to play on doubts about the Illinois senator's religion and background.
At the rally in Pennsylvania, Bill Platt, a local Republican party representative, twice used Obama's middle name before McCain arrived to speak.
McCain has previously apologised for using the name, which draws allusions to Saddam Hussein, the late ruler of Iraq, calling it "improper and inappropriate".
The McCain campaign issued a statement after the rally saying it did not condone "this inappropriate rhetoric".