But among overall registered voters Walker still holds a small lead with 47.5 percent to Burke with 44.1 percent, the poll found.
Those findings contrast with the last two previous Marquette University polls which showed a dead heat in the race.
The latest poll's findings underscore how Burke has become a serious challenger to Walker.
The poll was conducted among 815 Wisconsin voters from Thursday through Sunday. The margin of error was plus or minus 3.5 percentage points. For the 609 people polled who identified as registered voters and said they were likely to vote the margin of error was 4.1 percent.
Prior to that poll the TPM Polltracker average gave Walker a slim 0.4 point lead over Burke in the race.