Updated

Republican gubernatorial challenger Bob Beauprez has jumped ahead of Colorado Democratic Gov. John Hickenlooper by 10 points in a poll released Wednesday, placing the once-popular incumbent behind by a substantial margin for the first time in the race.

In a contest that past polls have said is deadlocked, the independent survey from Connecticut-based Quinnipiac University has Beauprez leading Hickenlooper 50 percent to 40 percent among likely voters -- a divide that puts Hickenlooper in the most uncomfortable position of his political career. Twice elected Denver mayor with ease, the successful restaurant and brew-pub owner then cruised into the governor's office four years ago, riding high on a public persona that showed him to be a quirky, approachable everyman.

With less than two months before the election, the poll suggests some of that sheen has worn off and Hickenlooper has a lot of ground to make up.

"Pundits were predicting that Gov. Hickenlooper faced a close race for reelection. Instead, he's got a mad dash to make up a double-digit deficit," assistant poll director Tim Malloy said in a statement.

In July, Quinnipiac conducted a poll of registered voters, instead of likely voters, that had the race tied.

The new poll was conducted by phone and surveyed 1,211 likely voters from Sept. 10-15. It has a margin of error of plus or minus 2.8 percentage points.

Republicans have spent months blasting Hickenlooper for granting an indefinite stay of execution to a death row inmate. And the Republican Governors Association has spent nearly $2 million in television ads criticizing him for the decision last year not to execute Nathan Dunlap, who was convicted of murder for the 1993 deaths of four people at an Aurora Chuck E. Cheese's.

The help from the RGA has helped offset some of Hickenlooper's vast fundraising advantage over Beauprez. The latest fundraising numbers show Hickenlooper has raised about $4.2 million, while Beauprez has raised about $1 million, and lent himself another $527,000.

Hickenlooper has pledged to run a positive campaign and not attack his opponent himself. His first television ad released last week focused on Colorado's improving economy.

The poll, however, shows voters giving Hickenlooper low marks on leadership, honesty and caring. Forty-eight percent of voters in the poll say they think Hickenlooper cares about their needs and problems. Another 51 percent say they think Hickenlooper has strong leadership qualities, while 48 percent say he's honest and trustworthy.

Female likely voters were divided, with 46 percent for Hickenlooper and 47 percent for Beauprez. But men overwhelmingly favor Beauprez 54 percent to 34 percent.

Independent voters make up about a third of Colorado's electorate, and they, too, favor Beauprez. He leads Hickenlooper among independent voters by a 50-37 percent margin.