(CNN) – A poll in Mitt Romney's home state of Michigan shows the GOP presidential nominee within three percentage points of President Barack Obama, a dramatic shift from one month ago when the president led his rival by double digits.

The EPIC-MRA survey released Monday showed Obama with the support of 48% of likely voters in Michigan, compared to 45% who said they support Romney. The gap was within the poll's sampling error.

That's a shift from an EPIC-MRA poll conducted September 8-11, which showed Obama leading Romney 47%-37%. The poll released Monday was conducted October 4-6, entirely after the first presidential debate between the two candidates.