Sunday's survey, by NBC News and The Wall Street Journal, showed the candidate were tied among likely voters with 47 percent each.
In the new survey, Obama, however, was leading Romney 49 percent to 44 percent among the wider pool of all registered voters.
But the poll also showed improved voter confidence in Romney.
A total 47 percent of registered voters said they were either optimistic and confident, or satisfied and hopeful, that Romney would do a good job as president. The figure marks a five-point increase since the last NBC/WSJ poll.
Obama's rating stood unchanged at 50 percent on this question.
Romney has also narrowed a gap on the public perception of his abilities as commander-in-chief. On that issue he now trails Obama by just three points -- 44 percent to 41 percent.
In the previous poll, the president had an eight-point edge on this question.
The poll, conducted on October 17-20 among 1,000 registered voters and 816 likely voters, had a margin of error of plus or minus 3.1 percentage points.
In the previous national NBC/WSJ poll, conducted before the debate season began, the president held a three-point lead over his Republican challenger -- 49 percent to 46 percent.