An independent survey of 1,200 likely Illinois voters also shows that Quinn would have a greater advantage over Brady, a downstate businessman and state senator, than Dillard, a suburban Chicago state senator.
Victory Research conducted the poll from Thursday through Sunday, starting on the day that Illinois Comptroller Dan Hynes conceded to Quinn the Democratic gubernatorial nomination.
Brady and Dillard, the top two vote-getters in the Republican primary, are locked in a waiting game as Illinois election officials certify results from the Feb. 2 primary. According to The Associated Press, just 406 votes separate the two men, with Brady in the lead.
In the poll, Quinn leads Brady by nearly 11 percentage points. His lead over Dillard is about half that size. Rich Whitney, the Green Party's nominee for governor, fares slightly better with Brady in the race, with 3.9 percent of the vote rather than 3.1 percent against Dillard and Quinn.
The poll lends credence to the argument that Quinn would have a better chance of beating Brady, the more conservative Republican candidate, than Dillard, perhaps the most left-leaning Republican contender in the gubernatorial primary.
But Victory pollster Rod McCulloch, who has previously conducted polls for Dillard and Quinn, says the difference in Quinn's lead over Brady versus Dillard has most to do with geography.
"Sen. Brady is not very well known yet in Cook County and the collar counties," McCulloch said in a statement this morning. "If Bill Brady is to have a chance to win this election, he will have to campaign hard in the traditionally Republican collar counties and suburban Cook County."
In the Republican primary, Brady picked up less than 6 percent of the vote in Cook, and barely more in surrounding counties. His support in downstate Illinois, where running television advertisements are less expensive than in the Chicago metropolitan area, is what launched him to the top of the GOP pack.
Brady has indicated that he is well aware of the challenges he faces in the Chicago area, where both Quinn and Dillard have stronger roots. During a press conference last week, he said his campaign was already brainstorming on how it would earn support in the most densely populated area of the state.
The poll has a 2.8 percent margin of error.