The Alaska U.S. Senate race has seen a “significant shift” in favor of Republican nominee Dan Sullivan, according to new polling data from The New York Times.

Democratic freshman incumbent Mark Begich had been leading Sullivan, the state’s former attorney general and a former Bush administration official.

But a disastrous ad campaign by Begich recently upended the race, and now, based on updated data from an online panel The Times monitors in conjunction with CBS News and YouGov, Sullivan has seen an 18-point swing in his favor. (RELATED: Attorney Slams Begich For Refusing To Take Down ‘Offensive’ Ad)

“The only significant shift came in Alaska, where the result flipped from Mark Begich, the Democrat, who used to lead by 12 points, to the Republican Dan Sullivan, who now leads by six,” The Times reported Sunday.

While the paper cautions against placing too much emphasis on its model due to Alaska’s small population size, it found evidence that a swing toward Sullivan mirrors actual voter sentiment.

“The swing toward Mr. Sullivan can’t be dismissed,” The Times states.

“Thanks to the panel data, it’s possible to see that much of the swing was indeed from panelists changing their answers: Six percent of repeated respondents shifted from “other” to Mr. Sullivan, along with 2 percent shifting from Mr. Begich to Mr. Sullivan.”

The Times identified two likely explanations for the move from Begich to Sullivan. Sullivan’s Aug. 5 primary triumph and a decision by tea party favorite Joe Miller to stay out of the race was beneficial. (RELATED: Democratic Sen. Mark Begich’s Ad Claim Rated ‘Pants On Fire’)

Begich’s attack ad failure was another. The incumbent attempted to slam Sullivan for the early prison release of a man who ended up murdering an Anchorage couple and sexually assaulting their two-year-old granddaughter.

But the evidence that Sullivan was responsible for man’s early release was not backed up by the facts. Making matters worse for Begich, the family of the victims, through their attorney, slammed his campaign for using their tragedy for political gain.

The Sullivan campaign jumped on the data panel’s findings.

“Even the New York Times agrees, not only are Mark Begich’s false attacks not working, they’re now moving Alaskans to support Dan Sullivan,” Sullivan for Senate spokesman Mike Anderson told The Daily Caller in a statement. “Survey after survey has shown this will be a close race because Mark Begich is in capable of defending his record of voting with Barack Obama 97% of the time and getting nothing done for Alaska.”

According to The Times, Republicans now have a 61 percent chance of taking control of the Senate, up from a 58 percent likelihood.

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